Document:

<PAGE>

                                OPTION AGREEMENT

         THIS OPTION AGREEMENT ("Agreement") is made and entered into as of this
27th day of August, 2001 by and among Williams Communications, LLC, a Delaware
limited liability company ("Williams"), and Winstar Wireless, Inc. ("Winstar"),
a Delaware corporation.

         WHEREAS, Williams has constructed or will construct or obtain rights of
use in a fiber optic communication system; and

         WHEREAS, Williams and Winstar entered into a Wireless Fiber(SM) IRU
Agreement effective as of December 17, 1998 (the "Wireless IRU Agreement"); and

         WHEREAS, Winstar desires to acquire from Williams, and Williams desires
to provide to Winstar, an option to enter into the new IRU agreement attached
hereto as Exhibit 1 (the "New IRU Agreement"); and

         WHEREAS, Williams wishes to enter into an amendment to the Wireless IRU
Agreement in the form of Amendment Number One to Wireless Fiber(SM) IRU
Agreement and Winstar is willing to so amend;

         NOW, THEREFORE, in consideration of the mutual covenants and agreements
contained herein, and for other good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged, the parties hereto, intending to be
legally bound, hereby agree as follows:

         1. Grant of Options. In consideration of Winstar's execution of
Amendment Number One to Wireless Fiber(SM) IRU Agreement and other good and
valuable consideration, the sufficiency of which is hereby acknowledged,
Williams grants to Winstar two options to enter into the New IRU Agreement
("Option 1" and "Option 2," respectively), which options are identical except
for the deadlines by which they may be exercised.

         2. Exercise of Option. In order to exercise either Option 1 or Option
2, Winstar shall deliver to Williams a notice of election (the "Notice of
Election") that specifies a date of commencement of the New IRU Agreement. The
New IRU Agreement shall become effective upon the date specified in the Notice
of Election as the date of commencement of the New IRU Agreement (the "New IRU
Commencement Date"), provided that Winstar has, on or before the New IRU
Commencement Date, executed and delivered to Williams a copy of the New IRU
Agreement, and provided, further, that, on or before the New IRU Commencement
Date, the Wireless IRU has been assumed pursuant to 11 U.S.C. Section 365 in a
confirmed plan of reorganization or has been assumed and assigned in connection
with an asset sale pursuant to 11 U.S.C. Section 363.

          3. Deadline for Exercise. The Notice of Election for Option 1 shall be
delivered, if at all, no later than December 31, 2001. The Notice of Election
for Option 2 shall be delivered, if at all, no sooner than January 1, 2002 and
no later than two (2) business days following the date on which an Order of the
United States Bankruptcy Court for the District of Delaware confirming a plan of
reorganization for Winstar (the "Plan") becomes a final order and the Plan has
become effective (the "Deadline for Exercise"). If neither Option I nor Option 2
is exercised

<PAGE>

by the Deadline for Exercise, or if Winstar's bankruptcy case is converted to a
Chapter 7 case, then both options shall expire, and Winstar shall immediately
return to Williams all original signature pages to the attached form of New IRU
Agreement executed by Williams. Williams agrees that it will not request,
directly or indirectly, that Winstar's bankruptcy case be converted to a Chapter
7 case.

         4. Assignment of Options. Winstar may assign this Agreement (and, in
the case of Section 4(e), below, pledge or grant a security interest in this
Agreement) without the prior written consent of Williams to:

                  (a) An entity that acquires all or substantially all of
         Winstar's assets,

                  (b) Any Affiliate of Winstar (as defined in the New IRU
         Agreement),

                  (c) A successor in a merger or acquisition of Winstar,

                  (d) An entity that acquires less than substantially all of
         Winstar's assets, provided that the entity has been determined to be
         financially solvent by mutual agreement or the assignment has been
         approved by the court; or

                  (e) In connection with any financing.

         5. Successors and Assigns. This Agreement shall be binding upon and
inure to the benefit of the parties hereto, and their respective
representatives, successors and permitted assigns.

         6. Notice. Unless otherwise provided in this Agreement, all notices and
communications concerning this Agreement shall be in writing and addressed to
the other party as follows, or at such other address as may be designated in
writing to the other party:

<Table>
<S>                                                       <C>
         IF TO WINSTAR:                                   IF TO WILLIAMS:

            Winstar Wireless, Inc.                           Williams Communications, LLC
            685 THIRD AVENUE                                 ONE WILLIAMS CENTER, SUITE 26-5
            NEW YORK, NY 10017                               TULSA, OKLAHOMA 74172
            Attn: EVP, GENERAL COUNSEL                       Attn: CONTRACT ADMINISTRATION

         WITH A COPY TO:                                  WITH A COPY TO:

            Winstar Wireless, Inc.                           Williams Communications, LLC
            2545 HORSE PEN ROAD                              ONE WILLIAMS CENTER, SUITE 4100
            HERNDON, VIRGINIA 22171                          TULSA, OKLAHOMA 74172
            Attn: VP, COMMERCIAL AND LEGAL OPERATIONS        Attn: GENERAL COUNSEL
</Table>

Unless otherwise provided herein, notices shall be hand delivered, sent by
registered or certified U.S. Mail, postage prepaid, or by commercial overnight
delivery service, and shall be deemed served or delivered to the addressee or
its office when received at the address for notice specified above when hand
delivered, on the day after being sent when sent by overnight delivery service,
and three (3) days after deposit in the mail when sent by U.S. mail.

                                        2

<PAGE>

         7. Entire Agreement. This Agreement, together with its Exhibit,
constitutes the entire understanding and agreement between the parties hereto
concerning the subject matter hereof, superseding all prior oral or written
agreement or understandings. This Agreement may not be terminated, amended,
modified or changed except in writing signed by the parties hereto.

         8. Governing Law. The validity, construction and performance of this
Agreement shall be governed by the laws of the State of New York, without giving
effect to conflicts of law principles thereof.

         9. Counterparts. This Agreement may be executed in one or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument. Such counterparts may be
exchanged by facsimile transmission (followed by delivery of the executed
original) and shall be deemed duly delivered upon acknowledgement of receipt
thereof by the recipient party.

         10. Interpretation. This Agreement is to be construed fairly and simply
and not strictly for or against either of the parties hereto. The Section
headings contained herein are for convenience of references only, are not part
of this Agreement, and shall not affect the meaning or interpretation of any
provision hereof.

          IN WITNESS WHEREOF and in confirmation of their consent to the terms
and conditions contained in this Agreement and intending to be legally bound
hereby, Williams and Winstar have executed and delivered this Agreement as of
the dates set forth below.

WINSTAR WIRELESS, INC.                    WILLIAMS COMMUNICATIONS, LLC

By:  /s/ C.Z. CZERNER                       By:  /s/ BRYAN J. DANCER
     -----------------------------              -------------------------------

Name:    C.Z. Czerner                       Name:      Bryan J. Dancer
     -----------------------------              -------------------------------

Title: Sr VP-Corporate Development        Title:  V.P. Business Development
      ----------------------------              -------------------------------

Date:  August 27, 2001                    Date:       8-27-01
     -----------------------------              -------------------------------

                                       3
<PAGE>
                                                                  EXECUTION COPY

                                  IRU AGREEMENT

                                     BETWEEN

                             WINSTAR WIRELESS, INC.

                                       AND

                         WILLIAMS COMMUNICATIONS, LLC

                              Dated
                                    -----------------

                                   (Long-Haul)

<PAGE>

                                  IRU AGREEMENT
                                   (Long-Haul)

         THIS IRU AGREEMENT (including the Exhibits and Schedules attached
hereto, this "Agreement") is made as of the New IRU Commencement Date
(hereafter defined) by and between WINSTAR WIRELESS, INC. ("Winstar"), a
Delaware corporation having its principal office at 685 Third Avenue, New York
City, New York 10017, and WILLIAMS COMMUNICATIONS, LLC ("Williams"), a Delaware
limited liability company, having its principal office at One Williams Center,
Tulsa, Oklahoma 74172.

                                   WITNESSETH:

         WHEREAS, Williams has constructed or will construct or obtain rights of
use in a fiber optic communication system (the "System") located along the
routes depicted in Exhibit A, Part I (the "Routes") and consisting of the System
Segments, as defined below; and

         WHEREAS, Winstar desires to acquire from Williams, and Williams desires
to provide to Winstar, the Network IRU as defined below upon the terms and
conditions set forth below;

         WHEREAS, Williams desires to sell and Winstar desires to buy certain
Services, as defined herein;

         NOW, THEREFORE, in consideration of the mutual promises set forth below
and other good and valuable consideration, the sufficiency of which is hereby
acknowledged, the parties hereby agree as follows:

1.       DEFINITIONS

         Capitalized terms and phrases used in this Agreement shall have the
following meanings:

                  (a)      "Acceptance" means the process of testing and
                           proofing the performance of the Winstar Fibers for
                           the purpose of delivery, set forth in Section 8 of
                           this Agreement, or the capacity or Service provided
                           under this Agreement as set forth in Section 5.2.
                           Winstar Fibers, capacity or Services which have been
                           accepted through the Acceptance process are
                           "Accepted."

                  (b)      "Acceptance Date" means the date on which the Winstar
                           Fibers are Accepted under Section 8.1 below.

                  (c)      "Acceptance Standards" means the standards set forth
                           in Exhibit D with respect to the testing of the
                           Winstar Fibers.

                  (d)      "Additional Services" means Telecommunications
                           Services in excess of the Capacity IRU, such excess
                           is not included in the Contract Price.

                                       1
<PAGE>

                  (e)      "Affiliate" means, with respect to any entity, any
                           other entity Controlling, Controlled by or under
                           common Control with such entity, whether directly or
                           indirectly through one or more intermediaries.

                  (f)      "Agreement" has the meaning set forth in the preamble
                           to this document.

                  (g)      "Ancillary Services" has the meaning set forth in
                           Section 6.4.

                  (h)      "Cable" means fiber optic cable installed pursuant to
                           this Agreement as part of the System (including any
                           replacement cable) and fibers contained therein,
                           including the Winstar Fibers, and associated splicing
                           connections, splice boxes and vaults, and conduit.

                  (i)      "Capacity" means the On-Net Telecommunications
                           Services set forth on Schedule B to this Agreement.

                  (j)      "Capacity IRU" has the meaning set forth in Section
                           2.1(b).

                  (k)      "Circuit" means a communications path with a
                           specified bandwidth.

                  (l)      "Claim" means any claim, action, dispute, or
                           proceeding of any kind between Winstar (or any of its
                           Affiliates, successors or assigns) and Williams (or
                           any of its Affiliates, successors or assigns) and any
                           other claim, transaction, occurrence, loss,
                           liability, expense or other matter arising out of, in
                           connection with, or in any way related to, the
                           Network IRU, the System, this Agreement or any other
                           instrument, arrangement or understanding related to
                           the Network IRU.

                  (m)      "Claimant" has the meaning set forth in Section 15.1.

                  (n)      "Collateral" has the meaning set forth in Exhibit K.

                  (o)      "Collocation Service" has the meaning set forth in
                           Exhibit C.

                  (p)      "Connecting Point" means a point where the network or
                           facilities of Winstar will connect to the System.

                  (q)      "Contract Price" means the purchase price for the
                           Network IRU in the gross amount of two hundred
                           forty-five million five hundred twenty seven thousand
                           two hundred dollars ($245,527,200.00), comprised of
                           one hundred two million three hundred ninety-seven
                           thousand six hundred eighty dollars ($102,397,630.00)
                           for the Winstar IRU and one hundred forty-three
                           million one hundred twenty-nine thousand five hundred
                           twenty dollars ($143,129,520.00) for the Capacity IRU
                           payable together in Monthly Payments, and is subject
                           to reduction by Section 8.4 and 13.1(b). or other
                           reductions allowed under this Agreement or as agreed
                           by the Parties.

                                      2
<PAGE>

                  (r)      "Control" and its derivatives mean legal, beneficial
                           or equitable ownership, directly or indirectly, of
                           more than fifty percent (50%) of the outstanding
                           voting capital stock (or other ownership interest, if
                           not a corporation) of an entity or management or
                           operational control over such entity.

                  (s)      "Costs" means actual, direct costs incurred and
                           computed in accordance with the established
                           accounting procedures used by Williams to bill third
                           parties for reimbursable projects. All Costs shall be
                           computed in accordance with generally accepted
                           accounting principles. Such actual, direct costs
                           include the following:

                           (i)      Labor costs, including wages and salaries,
                                    and benefits, plus the overhead allocable to
                                    such labor costs (overhead allocation
                                    percentage shall not exceed the lesser of:
                                    (i) the percentage Williams allocates to its
                                    internal projects; or (ii) thirty percent
                                    (30%)); and

                           (ii)     Other direct costs and out-of-pocket
                                    expenses on a pass-through basis (such as
                                    equipment, materials, supplies, contract
                                    services, costs of capital, Required Rights,
                                    sales, use or similar taxes, etc.) plus ten
                                    percent (10%) of such expenses; but,

                           (iii)    Less any cost or expense reimbursed by a
                                    third party.

                  (t)      "Cover" means the remedy for late delivery of the
                           Winstar Fibers provided in Section 8.3 of this
                           Agreement.

                  (u)      "Deduction Section" has the meaning set forth in
                           Section 25.1(l).

                  (v)      "Due Date" has the meaning set forth in Section 13.1.

                  (w)      "Facility Owners/Lenders" means any entity (other
                           than Williams) that: (a) owns any portion of the
                           System or any property or security interest therein,
                           (b) leases to Williams, or provides an IRU to
                           Williams in, any portion of the System, or (c) is a
                           Lender with respect to Williams or any Affiliates of
                           Williams.

                  (x)      "FCC" means the Federal Communications Commission.

                  (y)      "Fiber Acceptance Testing" means the fiber acceptance
                           testing described in Exhibit D.

                  (z)      "Fibers" means any optical fibers contained in the
                           System including the Winstar Fibers, the fibers of
                           Williams and the fibers of any third party in the
                           System excluding, however, any fibers granted
                           (whether through ownership, IRU, lease, or otherwise)
                           to governmental entities in exchange

                                      3
<PAGE>

                           for the use of streets, rights of way, or other
                           property under the jurisdiction of such entity.

                  (aa)     "Force Majeure Events" has the meaning set forth in
                           Article 23.1.

                  (bb)     "Indefeasible Right of Use" or "IRU" means an
                           exclusive, indefeasible right to use the specified
                           property or capacity in the manner contemplated by
                           this Agreement; provided, however, that the grant of
                           an IRU shall not convey title, ownership, or rights
                           of possession in the System, the Winstar Fibers, the
                           Cable, the Right-of-Way Agreements, or any other real
                           or personal property.

                  (cc)     "Indemnitor" has the meaning set forth in Section
                           15.1.

                  (dd)     "Intellectual Property Rights" means patent,
                           copyright, trademark, trade secret or other
                           proprietary rights with respect to any work product
                           in which such rights could inure.

                  (ee)     "Interconnection" means the connections of the
                           Winstar equipment with the Williams Network or
                           third-party networks.

                  (ff)     "Interim Agreement" means the Interim Agreement by
                           and between the Parties executed on August 15, 2001.

                  (gg)     "Interim Services" means the Services provided to
                           Winstar pursuant to the Interim Agreement.

                  (hh)     "IRU Term" has the meaning set forth in Section 10.1.

                  (ii)     "LEC" means a local exchange carrier.

                  (jj)     "Lender" has the meaning set forth in Section 2.2.

                  (kk)     "Losses" means all liabilities, damages and related
                           costs and expenses (including fines, levies,
                           assessments, reasonable legal fees and disbursements
                           and costs of investigation, litigation, settlement,
                           judgment, interest and penalties) directly incurred
                           by a party.

                  (ll)     "Material Improvements" has the meaning set forth in
                           Exhibit C-1.

                  (mm)     "Mean Time to Restore" has the meaning set forth in
                           the applicable schedules of Exhibit B.

                  (nn)     "Minimum Term Liability" has the meaning set forth in
                           Section 5.3(b).

                  (oo)     "Monthly Payments" means the monthly amounts payable
                           to Williams for the Winstar IRU and the Capacity IRU
                           combined together granted under this Agreement as set
                           forth in Sections 3.1.

                                       4
<PAGE>

                  (pp)     "NCC" means Network Control Center, as set forth in
                           Exhibit I, Section 1(A).

                  (qq)     "Network IRU" has the meaning set forth in Section
                           2.1.

                  (rr)     "New IRU Commencement Date" means the date upon which
                           the Network IRU is made effective pursuant to the
                           terms of the Option Agreement, which shall be no
                           earlier than the day after day on which the first
                           monthly installment of the Monthly Payment is paid to
                           Williams, and shall be the date on which this
                           Agreement becomes effective.

                  (ss)     "Notice of Election" has the meaning set forth in
                           Section 15.2(a).

                  (tt)     "OOS" means Out-of-Spec, as set forth in Exhibit D,
                           Section 1(B).

                  (uu)     "Off Net" means a Circuit that is not On Net.

                  (vv)     "On Net" means a Circuit traversing the Williams
                           Network between two Williams points of presence.

                  (ww)     "OTDR" means optical time domain reflectometer, as
                           set forth in Exhibit D, Section 1(A).

                  (xx)     "Other Services" means local access, Interconnection,
                           Ancillary Services and Collocation Services.

                  (yy)     "Payment Deductions" has the meaning set forth in
                           Section 25.1(e).

                  (zz)     "Payment Terms" has the meaning set forth in Section
                           3.1.

                  (aaa)    "Point of Presence" or "POP" means a specified
                           location at which Williams originates or terminates
                           services.

                  (bbb)    "Premises" has the meaning set forth in Exhibit C.

                  (ccc)    "Prime Rate" means, with respect of any period, the
                           rate published as Chase Manhattan's prime rate in the
                           Wall Street Journal, or any successor publication
                           thereto, from time to time during such period. (mmm)
                           "Pro Rata Share" means a proportion equal to a
                           fraction, the numerator of which is the number of
                           Winstar Fibers and the denominator of which is all
                           Fibers in the relevant System Segment Portion(s). If
                           this fraction varies over different System Segment
                           Portions, then the Pro Rata Share shall be equal to
                           the weighted average (weighted by length as set forth
                           in Williams' as-built drawings) of the relevant
                           System Segment Portions. For example, if the fraction
                           for 100 feet of the relevant System Segment Portion
                           is 0.1 and the fraction for the remaining 50 feet of
                           the relevant System Segment

                                      5
<PAGE>

                           Portion is 0.07, the weighted average for the entire
                           System Segment Portion would be 0.09.

                  (ddd)    "Released Party" means each of the following (but
                           excludes Williams and Winstar):

                           (i)      Any Affiliates or Lenders of the other party
                                    and any Facility Owners/Lenders;

                           (ii)     Any employee, officer, director,
                                    stockholder, partner, member, or trustee of
                                    the other party or of its Affiliates,
                                    Lenders, or Facility Owners/Lenders; or

                           (iii)    Assignees of the entities included in the
                                    above subparagraphs (a) or (b) and any
                                    employee, officer, director, stockholder,
                                    partner, member, or trustee of such
                                    assignees.

                  (eee)    "Representatives" has the meaning set forth in
                           Section 20.2(a).

                  (fff)    "Requested Start Date" means the date specified as
                           delivery date in a Service Order.

                  (ggg)    "Required Rights" has the meaning set forth in
                           Section 4.1.

                  (hhh)    "Right-of-Way Agreements means rights, licenses,
                           authorizations, easements, leases, fee interests, or
                           agreements that provide for the occupancy by the
                           System of real property or fixtures (such as conduit,
                           bridges, river crossings, or transmission towers).

                  (iii)    "Route" has the meaning set forth in the Recitals
                           above.

                  (jjj)    "Routine Maintenance" has the meaning set forth in
                           Section 11.1.

                  (kkk)    "Security Interest" has the meaning set forth in
                           Exhibit K.

                  (lll)    "Service Orders" has the meaning set forth in
                           Section 5.2(a).

                  (mmm)    "Service Term" means with respect to the provision of
                           Telecommunications Services, Additional Services or
                           Other Services, the length of time specified in the
                           applicable Service Order during which Williams will
                           provide such Telecommunications Services, Additional
                           Services or Other Services

                  (nnn)    "Space" has the meaning set forth in Section 1.1 of
                           Schedule C.

                                      6
<PAGE>

                  (ooo)    "Start Date" means, with respect to any
                           Telecommunications Services or Other Services Winstar
                           requests Williams to provide hereunder, the first day
                           on which such services are provided.

                  (ppp)    "System" shall have the meaning set forth in the
                           Recitals above.

                  (qqq)    "System Segment" means one of the System Segment
                           Portions identified as a System Segment in Exhibit A,
                           Part 2.

                  (rrr)    "System Segment Portion" means a discrete portion of
                           the System and may refer to a span (a portion of the
                           System between two Transmission Sites or between a
                           Transmission Site and a Point of Presence or System
                           end point), a portion between two Points of Presence
                           or a Point of Presence and a System end point, or a
                           portion of the System affected by a relocation or
                           other circumstance.

                  (sss)    "Telecommunications Services" means interexchange
                           telecommunications capacity on Williams' Network (or
                           third parties' telecommunications facilities) at the
                           DS-3, OC-3, OC-12 and OC-48 levels but excluding
                           Other Service.

                  (ttt)    "Term" has the meaning set forth in Section 10.1.

                  (uuu)    "Third Party Service Provider" means any third party
                           provider, operator or maintenance repair contractor
                           of facilities employed by Williams in connection with
                           the provision of the Network IRU, Telecommunications
                           Services or Other Services.

                  (vvv)    "Transmission Sites" means the optical amplifier,
                           regenerator, and junction sites along each System
                           Segment.

                  (www)    "UCC" shall mean the Uniform Commercial Code as in
                           effect in the State of New York, as it may be amended
                           from time to time.

                  (xxx)    "Williams" means Williams Communications, LLC, a
                           Delaware limited liability company, formerly known as
                           Williams Communications, Inc.

                  (yyy)    "Williams Network" means the telecommunications
                           facilities owned or operated by Williams and used to
                           provide services between the cities listed on
                           Williams published POP list, as such may be added to
                           as Williams grows its network during the Term.

                  (zzz)    "Winstar" has the meaning set forth in the first
                           paragraph of this document.

                                        7
<PAGE>

                  (aaaa)   "Winstar Equipment" means optronic (opto-electrical),
                           electronic, or optical equipment, or materials,
                           facilities, or other equipment (other than the
                           System) owned, possessed, or utilized by Winstar

                  (bbbb)   "Winstar Facilities" has the meaning set forth in
                           Section 27.3.

                  (cccc)   "Winstar Fibers" has the meaning set forth in Section
                           2.1.

                  (dddd)   "Winstar IRU" has the meaning set forth in Section
                           2.1.

                  (eeee)   "Wireless IRU" shall mean that certain contract
                           entitled "Wireless Fiber IRU Agreement by and
                           between Winstar Wireless, Inc. and Williams
                           Communications, Inc.," effective as of December 17,
                           1998.

2.       CONVEYANCE OF DARK FIBER IRUS AND GRANT OF OPTION

         2.1.     GRANT OF NETWORK IRU.

                  In consideration of the payment of the Contract Price to
                  Williams as set forth herein and upon the New IRU Commencement
                  Date, Williams hereby grants the "Network IRU" to Winstar for
                  the purposes described herein and on the terms and subject to
                  the conditions set forth herein. The Network IRU comprises:

                  (a)      An exclusive Indefeasible Right of Use (the "Winstar
                           IRU"), effective as of the Acceptance Date for each
                           System Segment effective on the New IRU Commencement
                           Date, in:

                  Two (2)  strands of optical fiber, in each System Segment,
                           throughout the length of the Route as specified in
                           Exhibit A-2 and four (4) strands of optical fiber on
                           the Houston to Atlanta System Segment, as specified
                           in Exhibit A-2 (the "Winstar Fibers"); and

                  (b)      An exclusive Indefeasible Right of Use in On-Net
                           Telecommunications Services (the "Capacity IRU"),
                           effective as of the IRU Commencement Date, for the
                           circuits identified in Exhibit H to the Interim
                           Agreement.

         2.2.     FINANCING ARRANGEMENTS.

                  Each party may, directly or through an Affiliate, enter into
                  financing arrangements (including secured loans, leases, sales
                  with lease-back, leases with lease-back arrangements,
                  purchase-money or vendor financing, conditional sales
                  transactions or other arrangements) with one or more financial
                  institutions, vendors, suppliers or other financing sources
                  (each a "Lender"), that, with respect to Williams, relate to
                  the System and, with respect to Winstar, relate to the Network
                  IRU (and not to

                                       8
<PAGE>

                  any physical property right in the System), subject to
                  Williams' rights pursuant to the Payment Terms.

         2.3.     INCLUSION IN WINSTAR'S BID PROCESS.

                  During the Term, anytime Winstar seeks to obtain domestic
                  interexchange telecommunications services to fulfill its
                  business requirements (including dark fiber, data, voice and
                  video circuits) it shall always include Williams in such
                  consideration if Williams is responsive to Winstar's requests
                  and Williams' products, when compared to similar offerings in
                  the marketplace, are of equivalent or better quality,
                  availability and price.

         2.4.     NO TITLE TO REALTY OR PERSONALTY.

                  Neither this Agreement nor the grant of the Network IRU
                  effected hereby conveys any form or type of title in any real
                  or personal property, including the System or any portion
                  thereof or in any transmission or other facilities or
                  equipment whether or not related to the provision of
                  Telecommunications Services, Other Services, or Additional
                  Services. Williams and Winstar intend that this Agreement
                  constitutes a contractual right of use and not a sale or lease
                  of the Winstar Fibers.

         2.5.     WILLIAMS SECURITY INTEREST.

                  (a)      Effect and Intention of this Section. Nothing in this
                           Section 2.5 shall vary, alter or modify the
                           provisions of Section 2.4 of this Agreement. The
                           grant of the Security Interest to Williams as set
                           forth in Exhibit K is not intended to and shall not
                           be construed to create any rights in any of the
                           Collateral in favor of Winstar which are not granted
                           by other provisions of this Agreement; provided,
                           however, that the provisions of this Section 2.5
                           shall be effective regardless of whether this
                           Agreement creates an IRU or some other interest in
                           the Winstar Fibers.

                  (b)      Security Interest. As security for the payment or
                           performance under this Agreement, as the case may be,
                           Winstar grants Williams the Security Interest set
                           forth in Exhibit K.

3.       CONSIDERATION FOR IRU

         3.1.     CONTRACT PRICE.

                  As consideration for the Network IRU, Winstar shall pay the
                  Contract Price in combined Monthly Payments, in the amount of
                  four hundred twenty six thousand six hundred fifty eight
                  dollars ($426,65S.00) for the Winstar IRU and five hundred
                  ninety six thousand three hundred seventy-three dollars
                  ($596,373.00) for the Capacity IRU, together for a Monthly
                  Payment of one million twenty-three thousand thirty-one
                  dollars ($1,023,031.00), subject to reduction by Section 8.4,
                  and 13.1(b) or other reductions allowed under this Agreement
                  or as agreed by the

                                        9
<PAGE>

                  Parties. The Monthly Payments shall be made in accordance with
                  the payment and other terms set forth in Section 13, Invoicing
                  and Payment and subject to the terms set forth in Exhibit K
                  (the "Payment Terms").

4.       CONSTRUCTION

         4.1.     CONSTRUCTION REPRESENTATIONS, WARRANTIES AND COVENANTS.

                  (a)      Williams represents, warrants and covenants that, as
                           of the Acceptance Date for each System Segment, it
                           (or the underlying facility owner on Williams'
                           behalf) shall have obtained the following rights
                           (collectively, the "Required Rights"):

                           (i)      all Right-of-Way Agreements necessary for
                                    the installation and use of that System
                                    Segment or Circuit, as the case may be;

                           (ii)     the rights to use those System Segment
                                    Portions it does not own and the right to
                                    grant the Network IRU with respect to such
                                    System Segment Portions or Circuits, as the
                                    case may be;

                  (b)      Williams represents, warrants and covenants that, for
                           each System Segment,

                           (i)      that System Segment has been designed,
                                    engineered, installed, and constructed in
                                    accordance with the specifications set
                                    forth in Exhibits D, E, and F; and

                           (ii)     throughout the Term, the exercise of rights
                                    by or on behalf of Williams' Facilities
                                    Owners/Lenders shall not deprive Winstar of
                                    the peaceful and quiet enjoyment of the
                                    Winstar IRU in that System Segment, or of
                                    the use of the Capacity IRU as specified in
                                    this Agreement.

         4.2.     RENEWAL OF REQUIRED RIGHTS.

                  Williams shall renew or replace, as necessary to the provision
                  of the Network IRU from time to time, the existing Required
                  Rights for each System Segment Term.

         4.3.     AS-BUILT DRAWINGS.

                  Within six (6) months after the Acceptance Date for any System
                  Segment, Williams shall provide Winstar with as-built drawings
                  for that System Segment which have not yet been provided, in
                  compliance with the specifications for as-built drawings set
                  forth in Exhibit H. Williams will provide all completed
                  as-built drawings within 30 days.

                                       10
<PAGE>

5.       ORDERING AND PROVISIONING

         5.1.     PROVISION OF CAPACITY SERVICE.

                  (a)      Inasmuch as the deployment of the System does not
                           currently reach all locations set forth in Part 1 of
                           Exhibit A, Williams shall provide, subject to
                           availability and on a non-discriminatory basis,
                           Telecommunications Services on the Williams Network
                           in accordance with the terms of this Agreement and
                           the terms located in Exhibit B. The
                           Telecommunications Services comprising the Capacity
                           IRU are fixed as of the date of execution of the
                           Interim Agreement and are specified in Attachment 1
                           to the Interim Agreement. All such Telecommunications
                           Services are deemed Accepted.

                  (b)      At the request of Williams, Winstar shall pay for
                           Other Services or Additional Services requested by
                           Winstar in writing in accordance with the terms of
                           this Agreement.

                  (c)      Winstar shall request Other Services and Additional
                           Services in writing through its authorized
                           representatives designated by Winstar in writing.
                           Winstar shall have no liability for and Williams
                           shall have no obligation to provide any Additional
                           Services or Other Services not placed by Winstar's
                           authorized representative.

         5.2.     SERVICE ORDERS FOR OTHER SERVICES AND ADDITIONAL SERVICES.

                  (a)      Additional Services, and Other Services requested by
                           Winstar hereunder shall be requested on Williams
                           Service Order forms in effect from time to time
                           ("Service Orders"). Each Service Order shall
                           reference this Agreement. In addition to issuing a
                           Service Order for such Service, Customer may order
                           certain Switched Voice Services in an electronic
                           batch format approved by Williams ("Batch Order").
                           Williams shall accept any Service Order under this
                           Agreement that complies with the terms and conditions
                           set forth herein, subject to availability and credit
                           approval at the time Winstar places such Service
                           Order. Williams reserves the right to reject a
                           Service Order that does not conform with the terms
                           and conditions of this Agreement and such
                           non-conforming Service Order shall have no force or
                           effect hereunder.

                  (b)      A Service Order is deemed accepted (subject to
                           availability) by Williams when Williams' Service
                           Delivery department transmits, within 3 business days
                           after receiving Winstar's Service Order, an
                           electronic Order Confirmation Document ("OCD") to
                           Winstar indicating that Winstar's order is being
                           processed by Williams; provided however, Williams
                           will not issue an OCD for Switched Voice Services.

                                       11
<PAGE>
                  (c)      Each Service Order will indicate a Requested Start
                           Date for the Circuit, the desired term of the
                           Circuit, specific city pairs, applicable bandwidth,
                           whether the Circuit(s) are to be expedited or
                           provided in normal intervals and any other parameters
                           required or information necessary to enable Williams
                           to provide the Service. In the event that Williams is
                           unable to meet Winstar's Requested Start Date,
                           Williams will notify Winstar of the date when
                           Williams believes the Service will be available and
                           Winstar's Requested Start Date will be changed to
                           reflect the number of days of delay or advance, as
                           appropriate. Failure of Williams to deliver by
                           Winstar's Requested Start Date shall not constitute a
                           default under this Agreement and Williams shall not
                           be liable to pay to Winstar any penalties or damages
                           for Williams' failure to meet Winstar's Requested
                           Start Date.

                  (d)      Any conflicting, different or additional terms and
                           conditions contained in Winstar's acknowledgment or
                           Service Order or elsewhere are deemed objected to by
                           Williams and shall not constitute part of this
                           Agreement. No action by Williams (including
                           fulfillment of such Service Order) shall be construed
                           as binding or estopping Williams with respect to such
                           conflicting, different or additional term or
                           condition, unless the Service Order containing said
                           term or condition has been signed by an authorized
                           representative of Williams.

                  (e)      Williams will issue to Winstar an electronic notice
                           that Service is available ("Turn Up Acknowledgement"
                           or "TUA"). The TUA will indicate that all the
                           relevant Service ordered through Williams has been
                           tested by Williams and that the Williams' Service
                           meets or exceeds the Technical Specifications set
                           forth in the relevant Service Schedule. The TUA will
                           also set forth the date Winstar's Service is
                           available for use by Winstar and upon which Williams
                           shall commence charging for the Service ("Circuit
                           Effective Billing Date").

                           Winstar shall be deemed to have accepted Service and
                           Williams shall begin billing for the Service as of
                           the Circuit Effective Billing Date, provided that, if
                           Winstar notifies Williams' Service Delivery
                           Department in writing within four (4) business days
                           of the Circuit Effective Billing Date that Williams'
                           Service is in material non-compliance with the
                           applicable Technical Specifications and if, upon
                           investigation, such material non-compliance is due
                           solely to Williams fault, then Williams shall correct
                           the non-compliance and make the appropriate
                           adjustment to Winstar's billings under this
                           Agreement. The occurrence of any such non-compliance
                           shall not constitute a default under this Agreement
                           and Williams shall not be liable to pay to Winstar
                           any penalties or damages resulting from any such
                           non-compliance, except for the Outage Credits
                           respecting On-Net Telecommunications Services
                           provided pursuant to Exhibit B. Charges for Service
                           begin accruing upon Circuit Effective

                                       12
<PAGE>
                           Billing Date, regardless of whether Winstar is
                           actually using the Services, or is ready to test and
                           accept the Services.

                  (f)      If Acceptance for any Circuit does not occur sixty
                           (60) days of the Deadline Date, Winstar may terminate
                           this Agreement with respect to the delayed Circuit by
                           notice to Williams.

         5.3.     CHANGES IN SERVICE PARAMETERS.

                  (a)      Winstar may disconnect Off-Net Telecommunications
                           Service, Other Services, or Additional Services
                           provided by a Third-Party Service Provider pursuant
                           to a Service Order by providing sixty (60) days'
                           prior written notice and paying any and all amounts
                           properly due that Provider for the affected Service
                           Order.

                  (b)      Following the relevant Start Date for any On-Net
                           service, including the Capacity IRU, Winstar may
                           disconnect or reconfigure that service upon sixty
                           (60) days' prior-written notice. If that action
                           relates to a Circuit that has not been in place for
                           at least one (1) year from its Start Date, Winstar
                           shall pay Williams an amount equal to the total of
                           the monthly charges for one year of service of such
                           Circuit, less the amount of monthly charges actually
                           paid at the time of service disconnection (the
                           "Minimum Term Liability").

6.       LOCAL ACCESS SERVICES

         6.1.     LOCAL ACCESS SERVICES.

                  Williams may obtain "Local Access Service" for Winstar, which
                  is defined as the telecommunications facilities or services
                  connecting a Winstar-designated termination point to a point
                  of presence ("POP") designated by Williams. The term Local
                  Access Service, as used throughout this Agreement, may include
                  both domestic U.S. and foreign Local Access Service. Winstar
                  shall execute a Letter of Agency, in a form provided by
                  Williams, authorizing Williams to interact directly with the
                  Local Access Service provider(s) to obtain the Local Access
                  Service. Winstar shall pay all charges including, without
                  limitation, monthly charges, usage charges, installation
                  charges, non-recurring charges, or applicable
                  termination/cancellation charges, of the Local Access Service
                  provider(s).

         6.2.     WILLIAMS' PROVISIONING, TESTING, AND CHARGING FOR LOCAL ACCESS
                  SERVICES.

                  For Local Access Services ordered by Williams, Williams shall
                  provision and conduct the initial testing of an
                  interconnection between the Williams' Service set forth in the
                  Service Order and the Local Access Service. Williams shall
                  coordinate the installation of the Local Access Service with
                  the Williams' Service.

                                       13
<PAGE>

                  Local Access Service charges shall accrue at the then-current
                  tariff rate (or the standard published rate, if there is no
                  tariff rate) of the Local Access Service provider. If the
                  applicable rate for Local Access Service is changed by the
                  Local Access Service provider, such changes will be passed
                  through to, and be borne by, Winstar. In the event Williams'
                  Services are not ready at the same time as the Williams'
                  ordered Local Access Service, Williams will not begin billing
                  Winstar for such Local Access Services until the related
                  Williams' Services are turned up.

         6.3.     WINSTAR ORDERED LOCAL ACCESS.

                  Winstar may, in conformance with Williams' policies on third
                  parties providing connectivity into a Williams' POP, order its
                  own Local Access Services from a vendor who has established
                  entrance facilities in Williams' POP ("Approved Vendor"). In
                  the event Winstar desires to order Local Access Services from
                  someone other than an Approved Vendor, Winstar must get
                  Williams' prior written permission, which shall not be
                  unreasonably withheld. In such event, the Local Access Service
                  provider shall directly bill Winstar for such Services.
                  Williams may charge Winstar for any associated entrance
                  facility or mileage charges if it provides Carrier Facility
                  Assignment ("CFA") to Winstar. Winstar shall ensure that the
                  Winstar-ordered Local Access Services are turned up at the
                  same time as the Williams' Services. If the Winstar-ordered
                  Local Access Services are not ready as of the Circuit
                  Effective Billing Date, Winstar shall nonetheless be obligated
                  to pay for Williams' Services as of the Circuit Effective
                  Billing Date, so long as the delay in the provision of the
                  Local Access Services is not attributable to Williams.

         6.4.     ANCILLARY SERVICES.

                  Williams may also provide other services to Winstar for
                  reasons including, but not limited to: (a) Winstar's request
                  to expedite Telecommunications Services availability to a date
                  earlier than Williams' published installation interval or a
                  previously accepted Start Date; (b) Telecommunications
                  Services redesign or other activity occasioned by receipt of
                  inaccurate information from Winstar; (c) Winstar's request for
                  use of routes or facilities other than those selected by
                  Williams for provision of the Telecommunications Services; and
                  (d) other circumstances in which extraordinary costs and
                  expenses are generated at the written request of Winstar and
                  incurred by Williams (collectively, "Ancillary Services").

7.       CONNECTION TO THE SYSTEM AND COLLOCATION

         7.1.     COLLOCATION.

                  Winstar shall have the right to use Transmission Sites along
                  the Route and to collocate equipment in Williams' points of
                  presence pursuant Exhibit C. Williams will provide the
                  collocation space requested in Exhibit A-3

                                       14
<PAGE>

                  pursuant to Exhibit C. Such Transmission Sites shall meet or
                  exceed the power and building requirements specified in
                  Exhibit C. Winstar shall provide, maintain, and for all
                  purposes be solely responsible for all Winstar Equipment at
                  Transmission Sites or other locations.

         7.2.     INTERCONNECTION.

                  Subject to the provisions herein, Winstar shall pay for and
                  arrange all connections of its facilities with the Winstar
                  Fibers. Winstar shall pay Williams for any Costs incurred as a
                  result of making such connections and shall at its own cost
                  obtain all rights from third parties required to make such
                  connections. Williams' Costs for any requested connection
                  shall be estimated and Winstar shall pay Williams eighty
                  percent (80%) of such estimate prior to the work being
                  performed by Williams. Winstar shall pay the balance of the
                  actual Costs incurred by Williams in making the connection
                  within thirty (30) days of receipt of an invoice therefor. In
                  the event the estimated Costs exceed the actual Costs,
                  Williams shall refund Winstar the difference. Such connections
                  shall be made only as set forth in Exhibit B.

8.       ACCEPTANCE AND TESTING OF FIBERS

         8.1      FIBER ACCEPTANCE TESTING.

                  Exhibit D sets forth Fiber Acceptance Testing procedures,
                  tests deliverables that Williams shall provide to Winstar, and
                  procedures for determining the Acceptance Date of a System
                  Segment.

         8.2      ACCEPTANCE DATE OBLIGATIONS.

                  As of the Acceptance Date of Winstar Fibers in any System
                  Segment:

                  (a)      Williams or the underlying facility owner shall have
                           obtained all rights, licenses, authorizations,
                           easements, leases, fee interests, or agreements that
                           provide for the occupancy by such System Segment of
                           real property or fixtures (such as conduit, bridges,
                           river crossings, or transmissions towers);

                  (b)      Williams shall have obtained by IRU agreement, lease
                           or otherwise the right to use any portion of the
                           System along the System Segment it does not own; and

                  (c)      such System Segment shall be designed, engineered,
                           installed, and constructed in accordance with the
                           specifications set forth in Exhibits D, E, and F.

                                       15
<PAGE>

                  The rights Williams is required to obtain pursuant to
                  Subsections (a) and (b) above are referred to as "Required
                  Rights." Consistent with the terms of this Section 8.2,
                  Williams shall renew or replace existing Required Rights
                  through the Term.

                  The System Segments previously Accepted by Winstar, including
                  those listed on Exhibit A-2, and identified as Accepted, are
                  deemed Accepted.

         8.3      TIMELY COMPLETION

                  The estimated completion dates for completion of construction,
                  installation, William' Fiber Acceptance Testing, and hand-over
                  of Williams' test results for each System Segment which has
                  not already been Accepted are set forth in Exhibit A-2
                  ("Estimated Completion Date"). The deadline date for actual
                  completion and testing of each System Segment which has not
                  already been Accepted shall be the later of one hundred and
                  twenty (120) calendar days after (a) the applicable Estimated
                  Completion Date for such System Segment, or (b) the Estimated
                  Completion Date for such System Segment (as extended due to
                  Force Majeure Events) or as expressly permitted by this
                  Agreement (the "Deadline Date"). If Williams does not meet the
                  Deadline Date for any System Segment, and the parties are
                  unable, in good faith, to agree to an alternative Deadline
                  Date, Winstar's sole and exclusive remedy for such failure
                  shall be to obtain Cover (as hereinafter defined) beginning on
                  the Deadline Date for the System Segments not made available
                  and ending on the date such System Segments are Accepted. The
                  term "Cover" shall mean, and shall be satisfied by Williams'
                  providing, at Williams' expense: (a) such capacity as is
                  required for Winstar to carry those Circuits it would have
                  migrated to the Winstar Fibers, and (b) such other capacity as
                  is needed to fulfill Winstar's increase in usage (based on
                  actual orders of its customers), until the Winstar Fibers are
                  Accepted. In any event, Williams will provide such Cover
                  capacity in ATM, private line, or frame relay formats, at
                  Winstar's option.

         8.4      TERMINATION RIGHT.

                  If the Acceptance Date does not occur within one hundred
                  eighty (180) days of the Deadline Date, Winstar may terminate
                  this Agreement with respect to the relevant System Segment by
                  written notice to Williams. Within thirty (30) calendar days
                  after receipt of such notice, Williams shall, as Winstar's
                  exclusive remedy for such non-occurrence, reduce the Monthly
                  Payment by the Pro Rata Share of the Monthly Payment relating
                  to the terminated System Segment and the parties shall have no
                  further obligations with respect to such System Segment. If
                  Winstar exercises its right to terminate the Agreement with
                  respect to the relevant System Segment, such termination shall
                  be Winstar's exclusive remedy for the delay or failure of
                  delivery.

                                       16
<PAGE>

9.       USE OF THE SYSTEM

         9.1.     USE OF WINSTAR FIBERS.

                  Winstar may use the Winstar Fibers for any lawful purpose in
                  accordance with the terms and conditions set forth in this
                  Agreement.

         9.2.    NOTICE OF DAMAGE.

                  Winstar shall promptly notify Williams of any matters
                  pertaining to any damage or impending damage to or loss of
                  System that are actually known to it and that could reasonably
                  be expected to adversely affect the System.

         9.3.     PRECAUTIONS.

                  Winstar shall take all reasonable precautions against any
                  damage proximately caused by Winstar to the System or to
                  fibers used or owned by Williams or third parties.

         9.4.     USE OF EQUIPMENT.

                  Neither party shall use, or allow others to use, equipment,
                  technologies, or methods of operation that adversely affect
                  the Williams Network or the System or the permitted use of the
                  Williams Network or the System by Williams or third parties or
                  their respective Fibers, equipment, or facilities associated
                  therewith. If Winstar uses equipment, technologies, and
                  methods of operation that are collectively either in accord
                  with Williams' practices or generally accepted industry
                  standards, Williams shall have the burden of demonstrating
                  that Winstar has breached the requirements of the preceding
                  sentence.

         9.5.     LIENS.

                  Winstar shall not, directly or indirectly, cause any part of
                  the System to become subject to any mechanic's lien,
                  materialman's lien, vendor's lien, or any similar lien whether
                  by operation of law or otherwise. If Winstar becomes aware
                  that it has breached its obligations under this Section, it
                  shall promptly: (a) notify Williams in writing, (b) cause such
                  lien to be discharged and released of record without cost to
                  Williams, and (c) indemnify Williams against all costs and
                  expenses (including reasonable attorneys' fees and court costs
                  at trial and on appeal) incurred in discharging and releasing
                  such lien.

                                       17
<PAGE>

10.      TERM

         10.1.    AGREEMENT TERM.

                  The term of this Agreement and the IRUs granted under it shall
                  begin on the New IRU Commencement Date and shall end twenty
                  (20) years from the Acceptance Date for the last of the System
                  Segments to be delivered (the "Term").

         10.2.    SERVICE ORDER TERM.

                  Each Service Order placed under this Agreement shall have its
                  own Service Order Term, as indicated on such Service Order. At
                  the end of the Service Order Term for any Service Order, such
                  Service Order shall continue on a month-to-month basis
                  ("Extension Period") unless either party gives written notice
                  to the other that such Service Order shall not be continued,
                  such notice to be delivered at least sixty (60) calendar days
                  before the end of the Service Order Term, or if during the
                  Extension Period, then upon at least thirty (30) calendar
                  days' prior written notice. Charges to Winstar, as set forth
                  in this Agreement, for Services provided by Williams during
                  the Service Order Term shall continue to apply to Winstar
                  throughout any Extension Period, unless modified pursuant to
                  the terms of this Agreement.

         10.3.    EFFECT OF TERMINATION.

                  No termination of this Agreement, the Capacity IRU or the
                  Winstar IRU shall affect the rights or obligations of any
                  party hereto:

                  (a)      With respect to any payment or the handling of a
                           disputed payment hereunder for services rendered
                           under this Agreement during the Term; or

                  (b)      Pursuant to Articles 15, 16, 17, 18, 20, 23 and 24.1
                           entitled Indemnification; Limitation of Liability;
                           Insurance; Taxes and Governmental Fees; Confidential
                           Information; Remedies and Dispute Resolution; and
                           Rules of Construction, respectively.

         10.4     TRANSITION.

                  (a) By the date occurring one hundred eighty (180) days prior
                  to the end of the Term, Williams and Winstar shall met and
                  negotiated in good faith a plan to transition all of Winstar's
                  traffic off of the Winstar Fibers and the Circuits on which
                  the Capacity is provided ("Transition Period"). Winstar shall
                  continue payment of the Monthly Payment for all Winstar Fibers
                  and all Circuits on which its traffic is present for so long
                  as its traffic is carried, provided that Winstar shall prepay
                  any charges for the Winstar Fibers or the Circuits if the
                  parties have agreed to extend such usage beyond the Term.

                                       18
<PAGE>

                 (b) If because of Winstar's default, the Agreement is
                 terminated before the end of the Term, Winstar may request a
                 "Transition Period" of up to one hundred twenty (120) days
                 during which to move its traffic from the Winstar Fibers and
                 the Circuits on which the Capacity is provided. If Winstar
                 wishes a Transition Period after termination due to Winstar's
                 default, Winstar must provide notice to Williams within
                 twenty-four (24) hours of receipt of the notice of default from
                 Williams along with payment in full in immediately available
                 funds for the total of the Monthly Payments for the entire
                 Transition Period.

11.      OPERATION. MAINTENANCE, AND REPAIR OF THE SYSTEM

         11.1.    ROUTINE MAINTENANCE.

                  During the Term, Williams shall perform all required
                  maintenance and repair work that:

                  (a)      is specifically identified as Routine Maintenance in
                           Exhibit I; or

                  (b)      has aggregate Costs incurred as a result of any
                           single event or multiple, closely related events less
                           than or equal to ten thousand dollars ($10,000.00) at
                           no additional cost to Winstar. "Routine Maintenance"
                           means the work specifically identified as Routine
                           Maintenance in Exhibit I, provided that Routine
                           Maintenance excludes work for which Winstar is
                           obligated to reimburse Williams for all or a portion
                           of the Costs incurred pursuant to other Articles of
                           this Agreement.

         11.2.    NON-ROUTINE MAINTENANCE.

                  Winstar shall pay its Pro Rata Share of Williams' direct Costs
                  of non-Routine Maintenance of the System in excess of ten
                  thousand dollars ($10,000), if the Cost of such work relating
                  to any single event or multiple related events is greater than
                  ten thousand dollars ($10,000.00).

         11.3.    SUBCONTRACTORS.

                  Williams may subcontract provisioning, testing, maintenance,
                  repair, restoration, relocation, or other operational and
                  technical services it is obligated to provide hereunder or may
                  have the underlying facility owner or its contractor perform
                  such obligations. Such subcontracting shall not relieve
                  Williams of any obligations under this Agreement.

         11.4.    WINSTAR EQUIPMENT.

                  Williams' maintenance and repair obligations under this
                  Agreement shall not include maintenance, repair or replacement
                  of Winstar Equipment.

                                       19
<PAGE>

         11.5     ACCESS TO SYSTEMS.

                  Winstar shall not access any physical part of any System
                  Segment without the prior written consent of Williams, and
                  then only upon the terms and conditions specified by Williams.

12.      RELOCATION

         12.1.    RELOCATION.

                  If, Williams determines for bona fide operational reasons, or
                  is required by a third party acting pursuant to condemnation
                  or similar authority or by a governmental entity, to relocate
                  all or any portion of such System Segment or any of the
                  facilities used or required in providing Winstar with the
                  Winstar IRU, Williams shall, to the extent practicable,
                  provide Winstar sixty (60) days' prior notice of any such
                  relocation and shall proceed with such relocation. Williams
                  shall have the right to direct such relocation, including the
                  right to determine the extent of, the timing of, and methods
                  to be used for such relocation, provided that any such
                  relocation:

                  (a)      Shall be constructed and tested in accordance with
                           the specifications and requirements set forth in this
                           Agreement and applicable Exhibits;

                  (b)      Shall not result in a materially adverse change to
                           the operations, performance, Connecting Points with
                           the network of Winstar, or end points of the System
                           Segment; and

                  (c)      Shall not unreasonably interrupt service on the
                           affected System Segment.

                  For purposes of this Section, a Williams' relocation shall be
                  for bona fide operational reasons if it is undertaken in good
                  faith (i) to settle or avoid a bona fide threatened or filed
                  condemnation action or order by a governmental authority to
                  relocate, (ii) to reduce the likelihood of physical damage to
                  the System, (iii) as the result of a Force Majeure Event, or
                  (iv) for other operational reasons to which Winstar has
                  consented, provided that Winstar shall not unreasonably
                  withhold such consent. Williams shall use reasonable efforts
                  to contest any exercise of condemnation authority that would
                  require a relocation that would require Winstar to reimburse
                  Williams pursuant to this Article 12.

         12.2.    COST OF RELOCATION.

                  Unless such relocation is necessitated by a breach of
                  Williams' obligations under this Agreement or is undertaken by
                  Williams for any reason other than those reasons set forth in
                  Section 12.1 above, Winstar shall reimburse Williams for the
                  Costs incurred in the same manner and to the same extent as is
                  set forth for reimbursement of Costs in this Agreement.

                                       20
<PAGE>

         12.3.    UPDATED AS-BUILT DRAWINGS.

                  At Winstar's written request, Williams shall deliver to
                  Winstar updated as-built drawings with respect to a relocated
                  portion of the System Segment within the later of one-hundred
                  eighty (180) days following the completion of such relocation
                  or thirty (30) days after receipt of Winstar's request.

13.      INVOICING AND PAYMENT

         13.1.    MONTHLY PAYMENT.

                  (a)      Winstar shall pay Williams the Monthly Payments
                           during the Term as set forth in Section 3.1 and in
                           accordance with Exhibit K.

                  (b)      The first payment shall be due and payable upon
                           Winstar's execution of this Agreement. If any payment
                           made under the Interim Agreement has not been used by
                           the obligations under the Interim Agreement, and such
                           payment under the Interim Agreement had been made in
                           cash, it shall be applied and Winstar shall receive a
                           credit toward the first payment in the amount of
                           the unused portion of any payment under the Interim
                           Agreement.

                  (c)      Each additional Monthly Payment shall be due and
                           payable thereafter on the same day of the month as
                           the date of execution of this Agreement; provided
                           however, that if any such date is not a day on which
                           banks in New York are open for business (each, a
                           "Business Day"), then the payment due thereon shall
                           be paid on the next Business Day.

                  (c)      The Network IRU described in this Agreement shall not
                           become effective until Williams' receipt of the
                           initial payment described above.

                  (d)      All other amounts due hereunder shall be due and
                           payable thirty (30) days from Winstar's receipt of
                           the invoice ("Due Date"). Winstar agrees to remit
                           payment to Williams at the remittance address set
                           forth in the applicable invoice.

         13.2.    FORM OF PAYMENT.

                  Winstar shall pay the Monthly Payment and any other amount due
                  hereunder by wire transfer of immediately available funds via
                  Automated Clearinghouse ("ACH") or wire transfer to Williams
                  Communications, LLC in care of Bank One, Chicago, Illinois,
                  ABA #071000013, Account #52-87235 or such other bank or
                  account as Williams may in writing direct Customer to remit
                  payment pursuant to the notice provisions of this Agreement.
                  Customer acknowledges and understands that all charges are
                  computed exclusive of any applicable taxes and additional
                  charges expressly provided herein. Such additional charges
                  shall be paid by Customer in addition to all other charges
                  provided for herein.

                                       21
<PAGE>

         13.3.    DISPUTED CHARGES.

                  (a)      Winstar may only dispute charges for Additional
                           Services or Other Services. Winstar shall pay
                           undisputed charges when such payments are due under
                           this Agreement. Winstar may withhold payment of
                           particular charges that Winstar disputes in good
                           faith and for which it promptly gives written notice
                           to Williams, stating the details of such dispute. The
                           parties shall promptly refer such matter to dispute
                           resolution in accordance with Section 24. If Winstar
                           withholds any disputed charges and such charges are
                           ultimately determined to be proper and payable to
                           Williams, Winstar shall ultimately pay such charges
                           to Williams plus interest at the Prime Rate from the
                           date such charges were originally due until the date
                           such charges are paid. No payment dispute shall be
                           grounds for Williams to withhold or diminish the
                           quality or quantity of any of the connectivity and
                           services provided hereunder.

                  (b)      Termination of this Agreement as suspension of
                           Services as set forth in this Section shall not
                           affect Winstar's obligation to pay for the Services.

         13.4.    LATE INTEREST.

                  If either Williams or Winstar fails to make any payment of any
                  undisputed amount due and payable under this Agreement when
                  due, such amounts shall accrue interest, from the date such
                  payment is due until paid, including accrued interest, at the
                  Prime Rate.

         13.5.    ADJUSTMENTS.

                  Williams may make corrections to its invoices to reflect
                  undercharges only for the period of two (2) years following
                  the Due Date of each invoice, or two (2) years following the
                  date the corresponding service is rendered, whichever is
                  later.

         13.6.    WILLIAMS' RIGHT TO ASSURANCE.

                  (a)      If at any time there is a material adverse change in
                           Winstar's creditworthiness or a material adverse
                           change in Winstar's financial position, then in
                           addition to any other remedies available to Williams,
                           Williams may elect, in its sole discretion, to demand
                           reasonable assurance of payment from Winstar,
                           including among others the posting of a deposit and
                           executing an agreement with Williams regarding the
                           use of any such deposit ("Deposit Agreement"), such
                           Deposit Agreement to be in form and substance
                           acceptable to both Parties.

                  (b)      A material adverse change in Winstar's
                           creditworthiness shall include, but not be limited
                           to: (i) Winstar's default of its obligations to
                           Williams under this Agreement; (ii) failure of
                           Winstar to make full payment of charges due hereunder
                           on or before the Due Date on two (2) or more
                           occasions

                                       22
<PAGE>

                           during any period of twelve (12) or fewer months;
                           (iii) acquisition of Winstar (whether in whole or by
                           majority or controlling interest) by an entity which
                           is insolvent ,or which owes past due amounts to
                           Williams or any Williams affiliate, or which is a
                           materially greater credit risk than Winstar.

                  (c)      A material adverse change in Winstar's financial
                           position shall include, but not be limited to a
                           decrease in net worth or working capital of five
                           percent (5%) or greater during any calendar quarter.

                  (d)      In the event of a Williams demand for assurance of
                           payment, if Winstar has not provided Williams with
                           assurance satisfactory to Williams within ten (10)
                           calendar days of Williams' notice of demand for such
                           assurance, then, in addition to any other remedies
                           available to Williams, Williams shall have the
                           option, in its sole discretion, to exercise one or
                           more of the following remedies: (i) cause the start
                           of any Service described in any previously executed
                           Service Order to be delayed pending receipt of such
                           financial statements or of the satisfactory
                           assurance; or (ii) decline to accept a Service Order
                           or other requests from Winstar to provide Service.

14.      DISCLAIMER OF WARRANTIES

         14.1.    PARTIES.

                  EXCEPT AS SPECIFICALLY SET FORTH IN THIS AGREEMENT, THE
                  PARTIES MAKE NO WARRANTY TO EACH OTHER OR ANY OTHER ENTITY,
                  WHETHER EXPRESS, IMPLIED OR STATUTORY, AS TO THE
                  MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OF ANY
                  FIBERS, THE SYSTEM, THE TELECOMMUNICATIONS SERVICES, ANY OTHER
                  SERVICES OR ANY ADDITIONAL SERVICES PROVIDED HEREUNDER OR
                  DESCRIBED HEREIN, OR AS TO ANY OTHER MATTER, ALL OF WHICH
                  WARRANTIES ARE HEREBY EXPRESSLY EXCLUDED AND DISCLAIMED.

         14.2.    FACILITY OWNERS/LENDERS.

                  NO FACILITY OWNERS/LENDERS HAVE MADE ANY REPRESENTATION OR
                  WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, TO WINSTAR
                  CONCERNING WILLIAMS, THE WINSTAR FIBERS, THE CABLE, OR THE
                  SYSTEM OR AS TO ANY OF THE MATTERS SET FORTH IN SECTION 14.1.

                                       23
<PAGE>

15.      INDEMNIFICATION

         15.1.    INDEMNIFICATION.

                  Each party ("Indemnitor") shall indemnify, defend, protect,
                  and hold harmless the other party, its employees, members,
                  managers, officers, agents, contractors, Facility
                  Owners/Lenders, and Affiliates (collectively and individually,
                  "Claimant"), from and against any and all Losses resulting or
                  arising from, relating to or incurred in connection with:

                  (a)      The Indemnitor's failure to observe or perform its
                           duties or obligations to third parties (e.g., duties
                           or obligations to its customers);

                  (b)      The Indemnitor's infringement or misappropriation of
                           Intellectual Property Rights of any third party;

                  (c)      The death or bodily injury of any agent, employee,
                           customer, business invitee or any other person to the
                           extent caused by the tortious conduct of the
                           Indemnitor;

                  (d)      The damage, loss or destruction of any real or
                           tangible personal property to the extent caused by
                           the tortious conduct of the Indemnitor;

                  (e)      Fines, penalties or other amounts payable due to the
                           Indemnitor's violation of applicable laws or
                           regulation; and

                  (f)      Any Claim, demand, charge, action, cause of action,
                           or other proceeding asserted against the Claimant but
                           resulting from an act or omission of the Indemnitor
                           in its capacity as an employer of a person.

         15.2.    THIRD PARTY CLAIMS.

                  With respect to third-party claims, the following procedures
                  shall apply:

                  (a)      Promptly after receipt of notice of the commencement
                           or threatened commencement of any civil, criminal,
                           administrative, or investigative action or proceeding
                           involving a Claim in respect of which the Claimant
                           will seek indemnification pursuant to this Article
                           15, the Claimant will notify the Indemnitor of such
                           Claim in writing. No failure to so notify the
                           Indemnitor will relieve the Indemnitor of its
                           obligations under this Agreement except to the extent
                           that its ability to defend such Claim is materially
                           prejudiced by such failure. Within fifteen (15)
                           calendar days following receipt of written notice
                           from the Claimant relating to any Claim, but no later
                           than ten (10) calendar days before the date on which
                           any response to a complaint or summons is due, the
                           Indemnitor will notify the Claimant in writing if the
                           Indemnitor elects to assume control of the defense
                           and settlement of that Claim (a "Notice of
                           Election").

                                       24
<PAGE>

                  (b)      If the Indemnitor delivers a Notice of Election
                           relating to any Claim within the required notice
                           period, the Indemnitor shall be entitled to have sole
                           control over the defense and settlement of such
                           Claim; provided that (i) the Claimant shall be
                           entitled to observe the defense of such Claim and to
                           employ counsel at its own expense to observe the
                           defense of such Claim, and (ii) the Indemnitor shall
                           obtain the prior written approval, not to be
                           unreasonably withheld or delayed, of the Claimant
                           before ceasing to defend against such Claim or
                           entering into any settlement of such Claim. After the
                           Indemnitor has delivered a Notice of Election
                           relating to any Claim in accordance with the
                           preceding paragraph, the Indemnitor shall not be
                           liable to the Claimant for any legal expenses
                           incurred by the Claimant in connection with the
                           defense of that Claim. In addition, the Indemnitor
                           shall not be required to indemnify the Claimant for
                           any amount paid or payable by the Claimant in the
                           settlement of any Claim for which the Indemnitor has
                           delivered a timely Notice of Election if such amount
                           was agreed to without the written consent of the
                           Indemnitor.

                  (c)      If the Indemnitor does not deliver a Notice of
                           Election relating to any Claim within the required
                           notice period or after delivering a Notice of
                           Election fails to defend the Claim, the Claimant
                           shall have the right to defend the Claim in such
                           manner as it may deem appropriate. The Indemnitor
                           shall promptly reimburse the Claimant for all
                           reasonable costs and expenses of such defense.

         15.3.    INDEMNIFICATION OF PROVIDERS.

                  Winstar shall indemnify and hold harmless Williams its
                  employees, members, managers, officers, agents, contractors,
                  facility owners/lenders, affiliates and any Third Party
                  Service Providers, acting in such capacity, from and against
                  all Losses arising out of or relating to the content of any
                  transmission by Winstar, including Claims relating to any
                  violation or alleged violation of export control laws or other
                  laws or failure to comply with Winstar's obligations as set
                  forth in Sections 27.4 and 27.5.

         15.4.    WINSTAR CUSTOMERS.

                  Winstar shall indemnify and hold Williams its employees,
                  members, managers, officers, agents, contractors, facility
                  owners/lenders, affiliates, acting in such capacity, harmless
                  from and against all Losses arising out of or relating to the
                  use of the Winstar Fibers by any Winstar customer.

                                       25

<PAGE>

16.      LIMITATION OF LIABILITY

         16.1.    GENERAL INTENT.

                  Subject to the specific provisions of this Article 16, it is
                  the intent of the Parties that each party shall be liable to
                  the other party for any actual damages incurred by the
                  non-breaching party as a result of the breaching party's
                  failure to perform its obligations in the manner required by
                  this Agreement.

         16.2.    LIABILITY RESTRICTIONS.

                  (a)      IN NO EVENT, WHETHER IN CONTRACT OR IN TORT
                           (INCLUDING BREACH OF WARRANTY, NEGLIGENCE AND STRICT
                           LIABILITY IN TORT), SHALL A PARTY BE LIABLE FOR
                           INDIRECT, CONSEQUENTIAL, EXEMPLARY, PUNITIVE OR
                           SPECIAL DAMAGES EVEN IF SUCH PARTY HAS BEEN ADVISED
                           OF THE POSSIBILITY OF SUCH DAMAGES IN ADVANCE.

                  (b)      Subject to Subsection (c), below, each party's total
                           liability to the other, whether in contract or in
                           tort (including breach of warranty, negligence and
                           strict liability in tort) shall be limited to two
                           hundred million dollars ($200,000,000).

                  (c)      The limitation set forth in Subsections (b), above,
                           shall not apply with respect to: (i) third-party
                           Claims subject to indemnification pursuant to the
                           Agreement; or (ii) fees due and owing under this
                           Agreement at the time of the Claim.

                  (d)      For the purposes of this Section 16.2 all amounts
                           payable  or paid to third parties in connection with
                           Claims that are eligible for indemnification pursuant
                           to this Agreement shall be deemed direct damages.

         16.3.    RELEASED PARTIES.

                  Neither party shall have any recourse of any kind against any
                  Released Party or any assets of a Released Party in respect of
                  any Claim that is not directly or indirectly caused by the
                  Released Party, it being expressly agreed and understood that
                  no liability whatsoever shall attach to or be incurred by any
                  Released Party in respect of any Claim under or by reason of
                  this Agreement or any other instrument, arrangement or
                  understanding relating to the Winstar IRU, the System, the
                  Capacity IRU, the Telecommunications Services, the Other
                  Services or Additional Services, except to the extent such
                  Claim is directly or indirectly caused by the Released Party.
                  Each party waives all such recourse to the extent set forth in
                  this Section on behalf of its successors, assigns, and any
                  entity claiming by, through, or under such party.

                                       26
<PAGE>

17.      INSURANCE

         During the Term, the parties shall each obtain and maintain not less
         than the insurance requirements in accordance with Exhibit C.

18.      TAXES AND GOVERNMENTAL FEES

         18.1.    PAYMENT BY WINSTAR.

                  Winstar shall timely report and pay any and all sales, use,
                  income, gross receipts, excise, transfer, ad valorem, or other
                  taxes, and any and all franchise fees or similar fees, if any,
                  assessed against it due to its ownership of the Network IRU,
                  its use of the Winstar Fibers, or use of the Capacity IRU
                  including the provision of services over the Winstar Fibers,
                  its use of any other part of the System, or its use of
                  facilities connected to the Winstar Fibers. Notwithstanding
                  the preceding sentence, if Winstar provides Williams with a
                  valid resale or other exemption certificate, Williams shall
                  not charge Winstar any taxes exempted by the resale of other
                  exemption certificate.

         18.2     PAYMENT BY WILLIAMS.

                  Subject to Section 18.1 above, Williams shall timely report
                  and pay any and all sales, use, income, gross receipts,
                  excise, transfer, ad valorem or other taxes, and any and all
                  franchise fees or similar fees assessed against it due to its
                  construction, ownership or use of the System, provided that
                  Winstar shall reimburse Williams for its Pro-Rata Share of
                  property taxes (including ad valorem, use, property, or
                  similar taxes, franchise fees, or assessments that are based
                  on the value of property or of a property right) attributable
                  to the System, including taxes based on the value, operation,
                  or existence of the System.

         18.3     REIMBURSEMENT.

                  If Williams is assessed for any taxes or fees (a) related to
                  Winstar's ownership of the Network IRU, Winstar's use of or
                  rights in the Capacity or Winstar Fibers, or (b) that Winstar
                  is obligated to pay pursuant to Sections 18.1 or 18.2,
                  Winstar shall reimburse Williams for any payment of such
                  taxes or fees within thirty (30) days of receipt of Williams'
                  invoice.

         18.4     COOPERATION.

                  The parties shall cooperate in any contest of any taxes or
                  fees so as to avoid, to the extent reasonably possible,
                  prejudicing the interests of the other party.

         18.5     SERVICES.

                  If any sales taxes, value added taxes or similar charges or
                  impositions are assessed against Williams after, or as a
                  result of, Winstar's use of Telecommunications

                                       27
<PAGE>
                  Services, any Other Services or the Additional Services by any
                  local, state, national, international, public or quasi-public
                  governmental entity or foreign government or its political
                  subdivision, to the extent Winstar has not provided a resale
                  or other exemption certificate, Winstar shall be solely
                  responsible for and shall pay such taxes, charges or
                  impositions and shall hold Williams harmless from any
                  liability or expense associated with such taxes, charges or
                  impositions. If Williams incurs any tax or charge levied to
                  support the Universal Service Fund contemplated by Section 254
                  the Communications Act of 1934 as amended, 47 U.S.C. Section
                  254, or its state or municipal equivalent, Winstar shall be
                  solely responsible for and agrees to reimburse Williams for
                  any such tax or charge.

19.      NOTICE

         Unless otherwise provided in this Agreement, all notices and
         communications concerning this Agreement shall be in writing and
         addressed to the other party as follows, or at such other address as
         may be designated in writing to the other party:

<Table>
<S>                                                         <C>
          IF TO WINSTAR:                                     IF TO WILLIAMS:
               WINSTAR WIRELESS, INC.                               WILLIAMS COMMUNICATIONS, INC.
               685 THIRD AVENUE                                     ONE WILLIAMS CENTER, SUITE 26-5
               NEW YORK, NY 10017                                   TULSA, OKLAHOMA 74172
               ATTN: EVP, GENERAL COUNSEL                            ATTN: CONTRACT ADMINISTRATION

          WITH A COPY TO:                                      WITH A COPY TO:

               WINSTAR WIRELESS, INC.                               WILLIAMS COMMUNICATIONS, INC.
               2545 HORSE PEN ROAD                                  ONE WILLIAMS CENTER, SUITE 4100
               HERNDON, VIRGINIA 22171                              TULSA, OKLAHOMA 74172
               ATTN: VP, COMMERCIAL AND LEGAL OPERATIONS             ATTN: GENERAL COUNSEL
</Table>

                  Unless otherwise provided herein, notices shall be hand
                  delivered, sent by registered or certified U.S. Mail, postage
                  prepaid, or by commercial overnight delivery service, and
                  shall be deemed served or delivered to the addressee or its
                  office when received at the address for notice specified above
                  when hand delivered, on the day after being sent when sent by
                  overnight delivery service, three (3) days after deposit in
                  the mail when sent by U.S. mail or, in the case of invoices,
                  upon the Due Date (as defined in the Telecommunications
                  Services Purchase Provision).

20.      CONFIDENTIALITY

         20.1.    CONFIDENTIAL INFORMATION.

                  Williams and Winstar each acknowledge that they may be
                  furnished with, receive, or otherwise have access to
                  information of or concerning the other party that such

                                       28
<PAGE>

                  party considers to be confidential, proprietary, a trade
                  secret or otherwise restricted. As used in this Agreement and
                  subject to the exclusions set forth in Section 20.3.
                  "Confidential Information" means all information, in any form,
                  furnished or made available directly or indirectly by one
                  party (the "Disclosing Party") to the other (the "Receiving
                  Party") that (i) concerns the operations, facilities, plans,
                  affairs and businesses of the Disclosing Party, the financial
                  affairs of the Disclosing Party, and the relations of the
                  Disclosing Party with its customers, employees and service
                  providers, or (ii) is marked confidential, restricted,
                  proprietary, or with a similar designation. The terms and
                  conditions of this Agreement shall be deemed Confidential
                  Information obligation.

         20.2.    OBLIGATIONS.

                  (a)      Each party's Confidential Information shall remain
                           the property of that party except as expressly
                           provided otherwise by the other provisions of this
                           Agreement. Each party shall each use at least the
                           same degree of care, but in any event no less than a
                           reasonable degree of care, to prevent unauthorized
                           disclosure of Confidential Information as it employs
                           to avoid unauthorized disclosure of its own
                           information of a similar nature. Except as otherwise
                           permitted hereunder, the parties may disclose such
                           information (A) to their respective directors,
                           officers, managers, employees, agents, contractors
                           and consultants (collectively, "Representatives") and
                           (B) entities performing services required hereunder
                           only where: (i) use of such entity is authorized
                           under this Agreement, (ii) such disclosure is
                           necessary or otherwise naturally occurs in that
                           entity's scope of responsibility, and (iii) the
                           entity agrees in writing to assume the obligations
                           described in this Section 20.2. Any disclosure to
                           such entity shall be under substantially the same
                           confidentiality terms and conditions as provided
                           herein.

                  (b)      Each party shall take reasonable steps to ensure that
                           its (and its Affiliates') Representatives comply with
                           this Section 20.2. In the event of any disclosure or
                           loss of, or inability to account for, any
                           Confidential Information of the Disclosing Party, the
                           Receiving Party shall promptly, at its own expense:
                           (i) notify the Disclosing Party in writing; (ii) take
                           such actions as may be necessary and cooperate in all
                           reasonable respects with the Disclosing Party to
                           minimize the violation and any damage resulting
                           therefrom.

                  (c)      Either party may disclose the terms and conditions of
                           this Agreement to any third party that (i) has
                           expressed a bona fide interest in consummating a
                           significant financing, merger or acquisition
                           transaction or other corporate transaction between
                           the third party and such party, (ii) has a reasonable
                           ability (financial or otherwise) to consummate such
                           transaction, and (iii) has executed a nondisclosure
                           agreement that includes within its scope the terms
                           and conditions of this Agreement and also includes a
                           procedure to limit the extent of copying and
                           distribution thereof. Each party shall

                                       29
<PAGE>

                 endeavor to delay the disclosure of the terms and conditions of
                 this Agreement until the status of discussions concerning such
                 transaction warrants such disclosure. In addition, either party
                 (or either party's Affiliates) may disclose the terms and
                 conditions of this Agreement as such party deems appropriate to
                 prepare for IPOs or major corporate transactions. Any
                 disclosure to such entity shall be substantially under the same
                 confidentiality terms and conditions as provided herein.

         20.3.    EXCLUSIONS.

                  "Confidential Information" shall exclude any particular
                  information that the Receiving Party can demonstrate:

                  (a)      At the time of disclosure, was in the public domain
                           or in the rightful possession of the Receiving Party;

                  (b)      After disclosure, is published or otherwise becomes
                           part of the public domain through no fault of the
                           Receiving Party;

                  (c)      Was received after disclosure from a third party who
                           had a lawful right to disclose such information to
                           the Receiving Party without any obligation to
                           restrict its further use or disclosure;

                  (d)      Was independently developed by the Receiving Party
                           without reference to Confidential Information of the
                           Disclosing Party; or

                  (e)      Was required to be disclosed to satisfy a legal
                           requirement of a competent government body; provided
                           that, immediately upon receiving such request and to
                           the extent that it may legally do so, the Receiving
                           Party advises the Disclosing Party promptly and prior
                           to making such disclosure in order that the
                           Disclosing Party may interpose an objection to such
                           disclosure, take action to assure confidential
                           handling of the Confidential Information, or take
                           such other action as it deems appropriate to protect
                           the Confidential Information.

         20.4.    No IMPLIED RIGHTS.

                  Nothing contained in this Section shall be construed as
                  obligating a party to disclose its Confidential Information to
                  the other party, or as granting to or conferring on a party,
                  expressly or impliedly, any rights or license to the
                  Confidential Information of the other party.

         20.5.    COMMUNICATION WITH FCC.

                  Communications by either party with the FCC regarding the
                  subject matter of this Agreement shall require the other's
                  prior written approval.

                                       30
<PAGE>

21.      DEFAULT

                  Subject to Williams' right of accelerated termination as set
                  forth in Exhibit K, a party shall not be in material breach of
                  this Agreement unless and until the other party provides it
                  written notice of default and the non-performing party has
                  failed to cure within thirty (30) days after receipt of such
                  notice. Any event of default may be waived in writing at the
                  non-defaulting party's option. Upon the failure of a party to
                  timely cure its material breach hereunder within the
                  applicable cure period, the non-defaulting party shall have
                  the right to (i) terminate this Agreement or (ii) subject to
                  the terms of Article 24, pursue any legal remedies it may have
                  under applicable law or principles of equity relating to such
                  breach.

22.      THE TERMINATION OF THIS AGREEMENT BY WINSTAR PURSUANT TO THE FOREGOING
         SHALL NOT RELIEVE WINSTAR OF ITS OBLIGATION TO PAY ANY AMOUNTS OWING ON
         THE CONTRACT PRICE OR OTHER AMOUNTS OWING TO WILLIAMS WHICH ACCRUED OR
         WERE INCURRED PRIOR TO THE DATE OF SUCH TERMINATION.

23.      FORCE MAJEURE

         23.1.    EXCUSABLE DELAY.

                  Neither Williams nor Winstar shall be in default under this
                  Agreement as a result of any delay in its performance (other
                  than a failure to make payments when due) caused by any
                  elements of nature or acts of God, fire, explosion, vandalism,
                  power outage, earthquake, flood or lightning; any civil or
                  military authority; by national emergency, insurrection,
                  rebellion, revolution, riot, civil disorders, war or act of
                  terrorism; by cable cuts; or any other cause beyond the
                  reasonable control of such party (collectively, "Force Majeure
                  Events"); provided, however, that (i) the non-performing party
                  is without fault in causing such default or delay, and (ii)
                  such default or delay could not have been prevented by
                  reasonable precautions and cannot reasonably be circumvented
                  by the non-performing party through the use of alternate
                  sources (e.g., other suppliers of telecommunications services
                  or capacity), workaround plans or other means, including means
                  contemplated by applicable disaster recovery processes or
                  procedures).

         23.2.    NOTICE AND REMEDY.

                  In such event the non-performing party shall be excused from
                  further performance or observance of the obligation(s) so
                  affected for as long as such circumstances prevail and such
                  party continues to use commercially reasonable efforts to
                  recommence performance or observance whenever and to whatever
                  extent possible without delay. The non-performing party shall
                  immediately notify the other party by telephone (to be
                  confirmed in writing within two (2) business days of the
                  inception of such delay) and describe at a reasonable level of
                  detail the

                                       31
<PAGE>

                  Force Majeure Event causing such delay and the expected
                  duration of the Force Majeure Event. The non-performing party
                  will provide the other party prompt written notice of the
                  cessation or termination of the Force Majeure Event.

24.      REMEDIES AND DISPUTE RESOLUTION

         24.1.    (a) DISPUTE RESOLUTION.

                  Any dispute between the Parties arising out of or relating to
                  this Agreement, the interpretation of any provision hereof or
                  the performance of Williams or Winstar shall be resolved as
                  provided in this Article 24. Notwithstanding the foregoing,
                  Winstar shall be obligated to make all Monthly Payments
                  without regard to the dispute process set forth herein.

                  (b) Cumulative Remedies.

                  Except as otherwise expressly provided herein, all remedies
                  provided for in this Agreement shall be cumulative and in
                  addition to and not in lieu of any other remedies available to
                  either party at law, in equity or otherwise.

         24.2.    INFORMAL DISPUTE RESOLUTION.

                  (a)      Prior to the initiation of any litigation, the
                           parties shall first attempt to resolve their dispute
                           at the chief executive officers level. Each Party's
                           CEO will meet to discuss the dispute, which may be in
                           person or by teleconference. This informal dispute
                           resolution requirement shall not delay the
                           institution of formal proceedings past any statute of
                           limitations expiration or for more than thirty (30)
                           days.

                  (b)      This Section 24.2 shall not be construed to prevent a
                           party from instituting, and a party is authorized to
                           institute, formal proceedings earlier to avoid the
                           expiration of any applicable limitations period, or
                           to preserve a superior position with respect to other
                           creditors or as provided in Exhibit K.

         24.3.    CONTINUED PERFORMANCE.

                  Each party agrees to continue performing its obligations under
                  this Agreement while any dispute is being resolved except to
                  the extent the issue in dispute precludes performance.

         24.4.    IMMEDIATE INJUNCTIVE RELIEF.

                  The only circumstance in which disputes between the parties
                  shall not be subject to the provisions of Section 24.2 is
                  where a party, in good faith, determines that a

                                       32
<PAGE>

                  temporary restraining order or other injunctive relief is its
                  only appropriate and adequate remedy. If a party seeks
                  immediate injunctive relief and does not prevail in
                  substantial part, that party shall pay the other party's costs
                  and attorneys' fees to the extent incurred in responding to or
                  challenging the request for immediate injunctive relief.

25.      GENERAL

         25.1.    RULES OF CONSTRUCTION.

                  (a)      The captions or headings in this Agreement are
                           strictly for convenience and shall not be considered
                           in interpreting this Agreement or as amplifying or
                           limiting any of its content. Words in this Agreement
                           that import the singular connotation shall be
                           interpreted as plural, and words that import the
                           plural connotation shall be interpreted as singular,
                           as the identity of the parties or objects referred to
                           may require. References to "person" or "entity" each
                           include natural persons and legal entities, including
                           corporations, limited liability companies,
                           partnerships, sole proprietorships, business
                           divisions, unincorporated associations, governmental
                           entities, and any entities entitled to bring an
                           action in, or that are subject to suit in an action
                           before, any state or federal court of the United
                           States.

                  (b)      Unless expressly defined herein, words having
                           well-known technical or trade meanings shall be so
                           construed.

                  (c)      Except as set forth to the contrary herein, any right
                           or remedy of Williams or Winstar shall be cumulative
                           and without prejudice to any other right or remedy,
                           whether contained herein or not.

                  (d)      Nothing in this Agreement is intended to provide any
                           legal rights to anyone not an executing party of this
                           Agreement except under the indemnification and
                           insurance provisions and except that (i) the Released
                           Parties shall have the benefit of Section 16.3,
                           25.2(a) and 25.5(a) and (ii) the Facility
                           Owners/Lenders shall be entitled to rely on and have
                           the benefit of Sections 14.2 and 25.5(b).

                  (e)      This Agreement has been fully negotiated between
                           Williams and Winstar.

                  (f)      In the event of a conflict between the provisions of
                           this Agreement and those of any Exhibit, the
                           provisions of the Exhibits shall prevail and this
                           Agreement shall be corrected accordingly.

                  (g)      Except as otherwise set forth herein, for the purpose
                           of this Agreement the normal standards of performance
                           within the telecommunications industry in the
                           relevant market shall be the measure of whether a
                           party's performance is reasonable and timely.

                                       33

<PAGE>

                  (h)      Except as the context otherwise indicates, all
                           references to Exhibits, Articles, Sections,
                           Subsections, Clauses, and Paragraphs refer to
                           provisions of this Agreement.

                  (i)      The failure of either Williams or Winstar to enforce
                           any of the provisions of this Agreement, or the
                           waiver thereof in any instance, shall not be
                           construed as a general waiver or relinquishment on
                           its part of any such provision, but the same shall
                           nevertheless be and remain in full force and effect.

                  (j)      This Agreement shall be governed by and construed in
                           accordance with the domestic laws of the State of New
                           York without reference to its choice of law
                           principles. All disputes referred to the statute of
                           limitations and the remedies for any wrongs that may
                           be found shall be governed by the laws of such state.
                           If a proceeding is brought for the enforcement of
                           this Agreement or because of any alleged or actual
                           dispute, breach, default or misrepresentation in
                           connection with any of the provisions of this
                           Agreement, the prevailing party shall be entitled to
                           recover reasonable attorneys' fees and other actual
                           and reasonable costs and expenses incurred in such
                           action or proceeding in addition to any other relief
                           to which such party may be entitled.

                  (k)      If any term, covenant or condition in this Agreement
                           shall, to any extent, be invalid or unenforceable in
                           any respect under the laws governing this Agreement,
                           the remainder of this Agreement shall not be affected
                           thereby, and each term, covenant or condition of this
                           Agreement shall be valid and enforceable to the
                           fullest extent permitted by law.

                  (1)      The parties acknowledge and agree that: (i) the
                           payment deductions ("Payment Deductions") set forth
                           in Sections 8.4. (collectively, the "Deduction
                           Section") shall not limit Williams' liability or
                           serve as a sole or exclusive remedy for Williams'
                           default under any portion of this Agreement; (ii)
                           Winstar may seek any other rights or remedies it may
                           have against Williams for any default hereunder;
                           (iii) the Deduction Section does not modify or
                           otherwise limit any other term or condition of this
                           Agreement; and (iv) Winstar's compliance with the
                           Deduction Section shall not constitute a breach of
                           the Payment Terms. Williams hereby waives any rights
                           it may have to use the Deduction Section as a claim
                           or defense against any other provision in this
                           Agreement.

         25.2.    ASSIGNMENT.

                  (a)      Except to the extent permitted by Section 25.2(d),
                           neither party may, or shall have the power to, assign
                           this Agreement (and, in the case of Section
                           24.2(a)(v), below, pledge or grant a security
                           interest in this Agreement) the

                                       34
<PAGE>

                           Winstar IRU or the Capacity IRU or delegate such
                           party's obligations hereunder without the prior
                           written consent of the other except to:

                           (i)      An entity that acquires all or substantially
                                    all of the assets of such party,

                           (ii)     Any Affiliate,

                           (iii)    A successor in a merger or acquisition of
                                    such party,

                           (iv)     An entity that acquires less than
                                    substantially all of the assets of such
                                    Party provided that the entity has been
                                    determined to be financially solvent by
                                    mutual agreement or the assignment has been
                                    approved by the court, or

                           (v)      In connection with any financing.

                           Provided, further, that a party may assign the
                           entirety of its rights and obligations under this
                           Agreement, or the Winstar IRU or the Capacity IRU,
                           individually, with the other party's consent, not to
                           be unreasonably withheld or delayed. In any case,
                           such consent shall not be withheld if the assignee
                           meets certain objective conditions such as credit
                           worthiness and other similar considerations and the
                           assignee agrees in writing to become bound by this
                           Agreement. If the potential assignor tenders a
                           commercially reasonable form of unconditional
                           guarantee of the potential assignee's performance
                           signed by the potential assignor and if such form
                           shall become legally binding upon the potential
                           assignor upon execution and delivery by the
                           non-assigning party, then the potential assignee
                           shall be deemed creditworthy unless it is insolvent
                           or subject to protection under the bankruptcy laws.
                           The rights of assignment expressed in this Section
                           24.2(a) are subject to the restrictions set forth in
                           Section 24.2(e), below:

                  (b)      Notwithstanding the foregoing, no assignment or other
                           transfer of this Agreement shall be effective without
                           the written agreement of the assignee to be bound by
                           the terms and conditions of this Agreement including
                           the indemnification provisions and limitations on
                           liability and recourse provision set forth in this
                           Agreement (including those benefiting the Released
                           Parties).

                  (c)      [intentionally omitted.]

                  (d)      The provisions of Section 25.2(a) notwithstanding,
                           Williams may assign some or all of its rights and
                           obligations hereunder to State Street Bank and Trust
                           Company of Connecticut, National Association, or its
                           successors, in connection with a financing by
                           Williams of construction of its fiber optic network.
                           In addition, State Street Bank and Trust Company of
                           Connecticut, National Association, or its successors,
                           may further assign

                                       35
<PAGE>

                           this Agreement as collateral for such financing. If
                           Williams makes an assignment pursuant to this
                           Subsection 25.2(d), Williams (or its assignee
                           pursuant to an assignment made under the other
                           provisions of this Section 25.2) shall guarantee
                           performance of the assignee's obligations.

                  (e)      Except in connection with an assignment of this
                           Agreement as provided herein, until the third (3rd)
                           anniversary of the Acceptance Date of any System
                           Segment, Winstar shall not sell the dark fiber, but
                           may place optronics in such System Segment and resell
                           capacity, wavelengths, windows or lambdas in any
                           increment. After such three (3) year period, Winstar
                           may convey an interest in the dark fiber provided
                           that Winstar shall serve as the sole point of contact
                           with Williams and no party receiving such interest
                           shall have any contract rights against or be in
                           privity of contract with Williams as a result of such
                           conveyance.

                  (f)      This Agreement and the rights and obligations under
                           this Agreement (including the limitations on
                           liability and recourse set forth in this Agreement
                           benefiting the other party and the Released Parties)
                           shall be binding upon and shall inure to the benefit
                           of Williams and Winstar and their respective
                           permitted successors and assigns.

                  (g)      Neither the provisions of this Article nor any other
                           provisions of this Agreement shall limit the ability
                           of any Facility Owners/Lenders or of any Released
                           Parties to assign their rights under this Agreement
                           and such Facility Owners/Lenders and Released Parties
                           may assign their rights hereunder at any time and
                           from time to time without the consent of, notice to,
                           or any other action by any other entity. The
                           provisions of this Agreement benefiting the Facility
                           Owners/Lenders and Released Parties shall inure to
                           the benefit of such entities and their respective
                           Affiliates, successors, and assigns.

                  (h)      Notwithstanding any presumptions under applicable
                           state law that a change in control of a party
                           constitutes an assignment of an agreement, a change
                           in control of a party, not made for purposes of
                           circumventing restrictions on assignment or of
                           depriving the other party of rights under this
                           Agreement, shall not be deemed an assignment for
                           purposes of this Agreement.

         25.3.    RELATIONSHIP OF THE PARTIES.

                  The relationship between Williams and Winstar shall not be
                  that of partners, agents, or joint venturers for one another,
                  and nothing contained in this Agreement shall be deemed to
                  constitute a partnership or agency agreement between them for
                  any purposes, including federal income tax purposes. Williams
                  and Winstar, in performing any of their obligations hereunder,
                  shall be

                                       36
<PAGE>

                  independent contractors or independent parties and shall
                  discharge their contractual obligations at their own risk.

         25.4.    PROHIBITION ON IMPROPER PAYMENTS.

                  Neither party shall use any funds received under this
                  Agreement for illegal or otherwise "improper" purposes.
                  Neither party shall pay any commission, fees or rebates to any
                  employee of the other party. If either party has reasonable
                  cause to believe that one of the provisions in this Article
                  has been violated, it, or its representative, may audit the
                  books and records of the other party for the sole purpose of
                  establishing compliance with such provisions.

         25.5.    ENTIRE AGREEMENT; AMENDMENT; EXECUTION.

                  (a)      This Agreement constitutes the entire and final
                           agreement and understanding between Williams and
                           Winstar with respect to the subject matter hereof and
                           supersedes all prior agreements (oral or written)
                           relating to the subject matter hereof, which are of
                           no further force or effect (including, without
                           limitation, the IRU Agreement between Winstar
                           Wireless, Inc. and Williams Communications, Inc.
                           dated December 17, 1998, (Long-Haul) and all
                           amendments, clarifications and modifications thereto,
                           and the Standstill Agreement among Winstar Wireless,
                           Inc., Winstar Communications, Inc. and Williams dated
                           May 8, 2001, as amended, and the Winstar Services
                           Agreement between Williams and Winstar GoodNet, dated
                           July 16, 1998, Contract Number 98R0675.00, provided
                           that any undisputed payment obligations accruing
                           prior to the Effective Date, shall be due and owing
                           under the terms of this Agreement). The Exhibits
                           referred to herein are integral parts hereof and are
                           made a part of this Agreement by reference.

                  (b)      This Agreement may only be amended, modified, or
                           supplemented by an instrument in a single writing
                           executed by duly authorized representatives of
                           Williams and Winstar. No such amendment,
                           modification, or supplement shall result in any
                           modification of (i) any indemnity benefiting any
                           Facility Owners/Lenders or their respective
                           Affiliates or (ii) any limitation of liability or
                           recourse benefiting any Released Parties that is
                           adverse to such Released Parties.

                  (c)      This Agreement may be executed in one or more
                           counterparts, all of which taken together shall
                           constitute one and the same instrument.

                  (d)      This Agreement may be duly executed and delivered by
                           a party by execution and facsimile delivery of the
                           signature page of a counterpart to the other party,
                           provided that, if delivery is made by facsimile, the
                           executing party shall promptly deliver a complete
                           counterpart that it has executed to the other party.

                                       37
<PAGE>

                  (e)      Unless otherwise expressly permitted in this
                           Agreement, Williams shall not make any changes to the
                           Exhibits or Schedules attached hereto that may have a
                           material adverse impact on the performance or
                           usability of the Telecommunications Services,
                           Additional Services or Other Services without
                           Winstar's prior written consent.

         25.6.    PUBLIC DISCLOSURES.

                  All media releases, public announcements, and public
                  disclosures relating to this Agreement or the subject matter
                  of this Agreement, including promotional or marketing
                  material, but not including announcements intended solely for
                  internal distribution or disclosures to the extent required to
                  meet legal or regulatory requirements shall be coordinated
                  with and shall be subject to approval by both parties prior to
                  release.

26.      REPRESENTATIONS, WARRANTIES AND COVENANTS

         26.1.    REPRESENTATIONS AND WARRANTIES.

                  In addition to any other representations and warranties
                  contained in this Agreement, each party hereto represents and
                  warrants to the other that:

                  (a)      It has the requisite corporate power to enter into,
                           execute, deliver, and perform its obligations under
                           this Agreement;

                  (b)      It has taken all requisite corporate action to
                           approve the execution, delivery, and performance of
                           this Agreement;

                  (c)      This Agreement constitutes a legal, valid and binding
                           obligation enforceable against such party in
                           accordance with its terms;

                  (d)      Its execution of and performance under this Agreement
                           shall not violate any applicable existing
                           regulations, rules, statutes, or court orders of any
                           local, state, or federal government agency, court, or
                           body;

                  (e)      It is not subject to any contractual or other
                           obligation that would prevent it from entering into
                           this relationship; and

                  (f)      It has not offered or provided any inducements in
                           violation of law or the other party's policies, of
                           which it has been given notice, in connection with
                           this Agreement.

         26.2.    ADDITIONAL WILLIAMS COVENANTS.

                  Excluding services provided by third parties other than
                  Williams' subcontractors, Williams covenants that
                  Telecommunications Services, Additional Services, and Other
                  Services shall be provided to Winstar in accordance with the
                  technical

                                       38
<PAGE>

                  specifications set forth in the applicable service schedule.
                  Williams further covenants that it shall use commercially
                  reasonable efforts under the circumstances to remedy any
                  delays, interruptions, omissions, mistakes, accidents or
                  errors in the Telecommunications Services, Additional Services
                  or Other Services provided hereunder and to restore such
                  Telecommunications Services or Other Services to compliance
                  with the terms hereof.

         26.3.    INFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS.

                  Each party represents, warrants and covenants to the other
                  that it shall perform its responsibilities under this
                  Agreement in a manner that does not infringe, or constitute an
                  infringement or misappropriation of, any Intellectual Property
                  Rights of any third party.

27.      USE OF TELECOMMUNICATIONS AND OTHER SERVICES

         27.1.    CONDITION TO PROVISION OF SERVICES.

                  As a condition to provision of the Services by Williams,
                  Winstar warrants that the Telecommunications Services or Other
                  Services shall not be used for any unlawful purpose and that
                  more than ten percent (10%) of the transmissions will be
                  interstate transmissions. The parties represent to each other
                  that this Agreement, to the extent it is subject to FCC
                  regulation, is an inter-carrier agreement not subject to the
                  filing requirements of Section 211 (a) of the Communications
                  Act of 1934, as amended.

         27.2.    INTRASTATE INTEREXCHANGE SERVICES.

                  Winstar may use any interexchange service provided under this
                  Agreement including any service provided by means of a
                  Backbone Agreement only if such interexchange service is used
                  for carrying inter-state (as defined by the FCC)
                  telecommunications (i.e., telecommunications subject to the
                  jurisdiction of the Federal Communications Commission).
                  Williams and its Affiliates shall not be obligated to make
                  available Telecommunications Services, Additional Services, or
                  other interexchange service on a Circuit with end points
                  within a single state or service on a Circuit which
                  originates/terminates at points both of which are situated
                  within a single state unless Winstar represents in writing
                  that such interexchange service or Circuits shall be used to
                  carry inter-state telecommunications (as defined by the FCC).

         27.3.    WINSTAR RESPONSIBILITIES.

                  Winstar has sole responsibility for installation, testing and
                  operation of facilities, services and equipment ("Winstar
                  Facilities") other than those specifically provided by
                  Williams as part of the Telecommunications Services or Other
                  Services as described in a Service Order. In no event will the
                  untimely installation or non-operation of Winstar Facilities
                  relieve Winstar of its obligation

                                       39
<PAGE>

                  to pay charges for the Service or Other Service after the
                  Requested Start Date as set forth in the Service Order.

         27.4.    CONSENTS.

                  As between the parties, Winstar shall be responsible for all
                  arrangements with copyright holders, music licensing
                  organizations, performers' representatives or other parties
                  for necessary authorizations, clearances or consents with
                  respect to transmission contents.

         27.5.    RESTRICTION OF TRANSMISSIONS.

                  Winstar will not transmit content, nor permit its customers to
                  transmit content that violates applicable law or carries an
                  unreasonable risk of leading to criminal, civil or
                  administrative proceedings or investigations against Williams
                  or Winstar.

         27.6     COMPLIANCE WITH REGULATIONS.

                  If the FCC, any state regulatory body, or any court, in each
                  case having competent jurisdiction, determines that any
                  provision of this Agreement violates any applicable rules,
                  policies, or regulations, both parties shall reasonably
                  cooperate to immediately bring this Agreement into compliance,
                  consistent with the intent of this Agreement.

         27.7     RELATED AGREEMENTS.

                  On August 27, 2001, Winstar and Williams executed the Option
                  Agreement and the Amendment to the Wireless IRU. Winstar and
                  Williams agreed then and affirm now that the execution of the
                  Option Agreement was consideration for the other party to
                  execute the amendment to the Wireless IRU, and the execution
                  of the amendment to the Wireless IRU was consideration for the
                  other party to execute the Option Agreement. Winstar and
                  Williams further agree that, if the option under the Option
                  Agreement is exercised, the Wireless IRU, as amended, and the
                  this Agreement are intended to be, and shall be treated for
                  all purposes as, a single integrated agreement. Accordingly,
                  in the event that Williams becomes the subject of a case under
                  the United States Bankruptcy Code, Williams agrees that the
                  Wireless IRU, as amended, and the this Agreement shall be
                  treated as a single integrated agreement for purposes of 11
                  U.S.C. 365.

         27.7     REASONABLENESS, CONSENTS AND APPROVALS.

                  (a)      Where this Agreement requires a party to assist or
                           cooperate, such requirement shall not be interpreted
                           to require materially more than a commercially
                           reasonable level of effort (i.e. the standard
                           applicable will not be "best efforts" or "exhausting
                           all available means").

                                       40
<PAGE>

                  (b)      Except where expressly provided as being in the sole
                           discretion of a party, where agreement, approval,
                           acceptance, consent, or similar action by either
                           party is required under this Agreement, such action
                           shall not be unreasonably delayed or withheld. An
                           approval or consent given by a party under this
                           Agreement shall not relieve the other party from
                           responsibility for complying with the requirements of
                           this Agreement, nor shall it be construed as a waiver
                           of any rights under this Agreement, except as and to
                           the extent otherwise expressly provided in such
                           approval or consent.

                                       41
<PAGE>

         IN WITNESS WHEREOF and in confirmation of their consent to the terms
and conditions contained in this Agreement and intending to be legally bound
hereby, Williams and Winstar have executed and delivered this Agreement as of
the dates set forth below.

WINSTAR WIRELESS, INC.                       WILLIAMS COMMUNICATIONS, LLC.

BY:                                          BY: /s/ BRYON J. DANCER
    -------------------------------              -------------------------------

NAME:                                        NAME:   Bryon J. Dancer
     ------------------------------                -----------------------------

TITLE:                                       TITLE:  V.P. Business Development
      -----------------------------                 ----------------------------

DATE:                                        DATE:   8-27-01
       ----------------------------                 ----------------------------

                                       42<PAGE>
                                                                   EXHIBIT 10.89

                                  MASTER LEASE

     THIS MASTER LEASE ("Lease") is executed and delivered effective as of this
13th day of September, 2001 (the "Effective Date"), and is entered into by and
among WILLIAMS HEADQUARTERS BUILDING COMPANY, a Delaware corporation ("Lessor"),
WILLIAMS TECHNOLOGY CENTER, LLC, a Delaware limited liability company
("Lessee"), and WILLIAMS COMMUNICATIONS, LLC, a Delaware limited liability
company ("Guarantor").

                                    RECITALS

     The circumstances underlying the execution and delivery of this Lease are
as follows:

     A. Capitalized terms used and not otherwise defined herein have the
respective meanings given them in Article II, below.

     B. On even date herewith, Lessor has purchased from Lessee One Technology
Center also known as Williams Technology Center, and other related assets all
located in Tulsa, Oklahoma (all of which comprise the Leased Properties as
defined hereinbelow).

     C. Lessor now wishes to lease the Leased Properties to Lessee, and Lessee
wishes to lease the Leased Properties from Lessor, on the terms and conditions
set forth in this Lease.

     D. As a material inducement to Lessor to enter into this Lease, Guarantor
desires to unconditionally guaranty the performance of all of Lessee's duties
and obligations hereunder.

     IN CONSIDERATION of the foregoing, the covenants and agreements contained
herein, and other good and valuable consideration the receipt and adequacy of
which are hereby acknowledged, Lessor, Lessee and Guarantor agree as follows:

                                    ARTICLE I

                                LEASEHOLD ESTATE

     1.1 LEASE. Upon and subject to the terms and conditions hereinafter set
forth, Lessor leases to Lessee, and Lessee leases from Lessor, the Leased
Properties. Each Facility is leased subject to all covenants, conditions,
restrictions, easements and other matters affecting such Facility, whether or
not of record, including the Permitted Encumbrances and other matters which
would be disclosed by an inspection of the Facility or by an accurate survey
thereof.

     1.2 INDIVISIBILITY. This Lease constitutes one indivisible lease of the
Leased Properties, and not separate leases governed by similar terms. The Leased
Properties constitute one economic unit, and the Base Rent and all other
provisions have been negotiated and agreed to based on a demise of all of the
Leased Properties as a single, composite, inseparable transaction and would have
been substantially different had separate leases or a divisible lease been
intended. Except as expressly provided herein for specific, isolated purposes
(and then only to the extent

                                       1
<PAGE>

expressly otherwise stated), all provisions of this Lease apply equally and
uniformly to all the Leased Properties as one unit. An Event of Default with
respect to any Leased Property is an Event of Default as to all of the Leased
Properties. The parties intend that the provisions of this Lease shall at all
times be construed, interpreted and applied so as to carry out their mutual
objective to create an indivisible lease of all the Leased Properties and, in
particular but without limitation, that for purposes of any assumption,
rejection or assignment of this Lease under 11 U.S.C. Section 365 of the
Bankruptcy Code, this is one indivisible and non-severable lease and executory
contract dealing with one legal and economic unit which must be assumed,
rejected or assigned as a whole with respect to all (and only all) the Leased
Properties covered hereby.

     1.3 TERMS. This Lease shall have the Category 1 FF&E Term for the Category
1 FF&E, the Category 2 FF&E Term for the Category 2 FF&E, and the Realty Term
for the Land and Leased Improvements (collectively the "Term" or "Terms").

                                   ARTICLE II

                                   DEFINITIONS

     2.1 DEFINITIONS. For all purposes of this Lease, except as otherwise
expressly provided or unless the context otherwise requires, (i) the terms
defined in this Article have the meanings assigned to them in this Article and
include the plural as well as the singular, (ii) all accounting terms not
otherwise defined herein have the meanings assigned to them in accordance with
GAAP as at the time applicable, (iii) unless otherwise specifically designated,
all references in this Lease to designated "Articles," Sections" and other
subdivisions are to the designated Articles, Sections and other subdivisions of
this Lease, and (iv) the words "herein," "hereof" and "hereunder" and other
words of similar import refer to this Lease as a whole and not to any particular
Article, Section or other subdivision.

         Additional Charges: All Impositions and other amounts, liabilities and
obligations which Lessee assumes or agrees to pay under this Lease, including
without limitation, any and all costs, expenses and charges relating to the
upkeep and operation of the Leased Properties.

         Affiliate: Any Person which, directly or indirectly, Controls or is
Controlled by or is under common Control with another Person.

         Approval Threshold: Five Hundred Thousand Dollars ($500,000.00).

         Assessment: Any governmental assessment on the Leased Properties or any
part thereof for public or private improvements or benefits, whether or not
commenced or completed prior to the date hereof and whether or not to be
completed within the Term.

         Assumed Indebtedness: Any indebtedness or other obligations expressly
assumed in writing by Lessor and secured by a mortgage, deed of trust or other
security agreement to which Lessor's title to the Leased Properties is subject.

                                       2
<PAGE>

         Award: All compensation, sums or anything of value awarded, paid or
received in connection with a total or partial Taking.

         Base Rent: Collectively the Category 1 FF&E Base Rent, the Category 2
FF&E Base Rent and the Realty Base Rent.

         Business Day: Any day that is not a Saturday, Sunday or other day on
which commercial banks in New York, New York or Dallas, Texas are authorized or
required by law to remain closed; provided that, when used in connection with a
Eurodollar Loan (as defined in the Credit Agreement), the term "Business Day"
shall also exclude any day on which banks are not open for dealings in dollar
deposits in the London interbank market.

         Capital Lease Obligations: With respect to any Person means the
obligations of such Person to pay rent or other amounts under any lease of (or
other arrangement conveying the right to use) real or personal property, or a
combination thereof, which obligations are required to be classified and
accounted for as capital leases on a balance sheet of such Person under GAAP,
and the amount of such obligations shall be the capitalized amount thereof
determined in accordance with GAAP.

         Category 1 FF&E: All of the tangible personal property as set forth on
EXHIBIT K.

         Category 1 FF&E Base Rent: During the Category 1 FF&E Term, the
Category 1 FF&E Base Rent shall be the sum computed as set forth on EXHIBIT L.

         Category 1 FF&E Expiration Date: September 12, 2006.

         Category 1 FF&E Term: Five (5) Lease Years commencing on the
Commencement Date and ending on the Category 1 FF&E Expiration Date.

         Category 2 FF&E: All of the tangible personal property as set forth on
EXHIBIT M.

         Category 2 FF&E Base Rent: During the Category 2 FF&E Term, the
Category 2 FF&E Base Rent shall be the sum computed as set forth on EXHIBIT N.

         Category 2 FF&E Expiration Date: September 12, 2004.

         Category 2 FF&E Term: Three (3) Lease Years commencing on the
Commencement Date and ending on the Category 2 FF&E Expiration Date.

         Center: The multi-story office building located on the Center Parcel,
commonly known as the One Technology Center and Williams Technology Center.

         Center Parcel: The real property more particularly described on EXHIBIT
A attached hereto and made a part hereof on which the Center is located.

                                       3
<PAGE>

         Central Plant: As defined in the Construction Completion Agreement.

         Change in Control: means

     (a) the acquisition of ownership, directly or indirectly, beneficially or
of record, by any Person other than Guarantor or WCG, of any ownership interest
in the Lessee;

     (b) the acquisition of ownership, directly or indirectly, beneficially or
of record, by any Person or group (within the meaning of Section 13(d) or 14(d)
of the Exchange Act and the rules of the SEC thereunder as in effect on the date
hereof) other than Guarantor, of interests representing more than thirty-five
percent (35%) of either (i) the aggregate ordinary voting power represented by
the issued and outstanding ownership interests of Lessee, Guarantor or WCG, or
(ii) the issued and outstanding ownership interests of Lessee, Guarantor or WCG;

     (c) occupation of a majority of the seats (other than vacant seats) on the
board of directors of Lessee, Guarantor or WCG, by Persons who were neither (i)
nominated by the respective board of directors of Lessee, Guarantor, or WCG nor
(ii) appointed by directors so nominated; or

     (d) the acquisition of direct or indirect Control of Lessee, Guarantor or
WCG, by any Person or group.

         Clean-Up: The investigation, removal, restoration, remediation and/or
elimination of, or other response to, Contamination, in each case to the
satisfaction of all governmental agencies having jurisdiction, in compliance
with or as may be required by Environmental Laws.

         Code: The Internal Revenue Code of 1986, as amended.

         Collateral: Whether now in existence or hereinafter created and/or
acquired, collectively all Leased Personal Property and Fixtures, and insurance
proceeds and products thereof, together with all books and records, computer
files, programs, printouts and other computer materials and records related
thereto.

         Commencement Date: The Effective Date.

         Condemnor: Any public or quasi-public authority, or private corporation
or individual, having the power of condemnation.

         Construction Completion Agreement. The Agreement of Purchase and Sale
and Construction Completion dated effective as of February 26, 2001, as amended,
between Lessor as Seller, and Lessee as Purchaser, covering a portion of the
Leased Properties.

                                       4
<PAGE>

         Construction Funds: The Net Proceeds and such additional funds as may
be deposited with Lessor by Lessee pursuant to Section 14.6 for restoration or
repair work pursuant to this Lease.

         Contamination: The presence, Release or threatened Release of any
Hazardous Materials at the Leased Properties in violation of any Environmental
Law, or in a quantity that would give rise to any affirmative Clean-Up
obligations under an Environmental Law, including, but not limited to, the
existence of any injury or potential injury to public health, safety, natural
resources or the environment associated therewith, or any other environmental
condition at, in, about, under or migrating from or to the Leased Properties.

         Control: The possession, directly or indirectly, of the power to direct
or cause the direction of the management or policies of a Person, whether
through the ability to exercise voting power, by contract or otherwise.
"Controlling" and "Controlled" have correlative meanings.

         Credit Agreement: The Amended and Restated Credit Agreement dated as of
September 8, 1999, among Guarantor, WCG, Bank of America, N.A., The Chase
Manhattan Bank, and other parties, as may be amended or waived from time to time
with respect to the financial covenants therein, a copy of which constituted as
of the Effective Date is attached hereto as EXHIBIT C.

         Date of Taking: The date on which the Condemnor has the right to
possession of the Leased Property that is the subject of the Taking or Partial
Taking.

         Debt: This includes, without duplication, (a) all obligations of such
Person for borrowed money or with respect to deposits or advances of any kind,
(b) all obligations of such Person evidenced by bonds, debentures, notes or
similar instruments, (c) all obligations of such Person under conditional sale
or other title retention agreements relating to property acquired by such
Person, (d) all obligations of such Person in respect of the deferred purchase
price of property or services (excluding (i) current accounts payable incurred
in the ordinary course of business and (ii) payment obligations of such Person
to the owner of assets used in a Telecommunications Business (as defined in the
Credit Agreement) for the use thereof pursuant to a lease or other similar
arrangement with respect to such assets or a portion thereof entered into in the
ordinary course of business), (e) all Debt of others secured by (or for which
the holder of such Debt has an existing right, contingent or otherwise, to be
secured by) any Lien on property owned or acquired by such Person, whether or
not the Debt secured thereby has been assumed, (f) all guarantees by such Person
of the Debt of others, (g) all Capital Lease Obligations of such Person
(provided that Capital Lease Obligations in respect of fiber optic cable
capacity arising in connection with exchanges of such capacity shall constitute
Debt only to the extent of the amount of such Person's liability in respect
thereof net (but not less than zero) of such Person's right to receive payments
obtained in exchange therefor), (h) all obligations, contingent or otherwise, of
such Person as an account party in respect of letters of credit and letters of
guaranty, and (i) all obligations, contingent or otherwise, of such Person in
respect of bankers' acceptances. The Debt of any Person shall include the Debt
of any other entity (including any

                                       5
<PAGE>

partnership in which such Person is a general partner) to the extent such Person
is liable therefor as a result of such Person's ownership interest in or other
relationship with such entity, except to the extent the terms of such Debt
provide that such Person is not liable therefor.

         Encumbrance: With respect to any asset, (a) any mortgage, deed of
trust, lien, pledge, hypothecation, encumbrance, charge or security interest in,
on or of such asset, (b) the interest of a vendor or a lessor under any
conditional sale agreement, capital lease or title retention agreement (or any
financing lease having substantially the same economic effect as any of the
foregoing) relating to such asset and (c) in the case of securities, any
purchase option, call or similar right of a third party with respect to such
securities.

         Environmental Audit: A written certificate, in form and substance
satisfactory to Lessor, from an environmental consulting or engineering firm
acceptable to Lessor, which states that there is no Contamination on the Leased
Properties and that the Leased Properties are otherwise in strict compliance
with Environmental Laws.

         Environmental Documents: Each and every (i) document received by Lessee
or any Affiliate from, or submitted by Lessee or any Affiliate to, the United
States Environmental Protection Agency and/or any other federal, state, county
or municipal agency responsible for enforcing or implementing Environmental Laws
with respect to the condition of the Leased Properties, or Lessee's operations
at the Leased Properties; and (ii) review, audit, report, or other analysis data
pertaining to environmental conditions, including, but not limited to, the
presence or absence of Contamination, at, in, or under or with respect to the
Leased Properties that have been prepared by, for or on behalf of Lessee.

         Environmental Laws: All federal, state and local laws (including,
without limitation, common law), statutes, codes, ordinances, regulations,
rules, orders, permits or decrees relating to the introduction, emission,
discharge or release of Hazardous Materials into the indoor or outdoor
environment (including without limitation, air, surface water, groundwater,
(land or soil) or otherwise relating to the manufacture, processing,
distribution, use, treatment, storage, transportation or disposal of Hazardous
Materials; or the Clean-Up of Contamination, all as are now or may hereinafter
be in effect.

         Equipment: Collectively, all the items of machinery and equipment as
defined in Article 9 of the UCC comprising part of the Leased Personal Property.

         ERISA: The Employee Retirement Income Security Act of 1974, as amended
from time to time.

         ERISA Event: (a) any "reportable event", as defined in Section 4043 of
ERISA or the regulations issued thereunder with respect to a Plan (other than an
event for which the 30-day notice period is waived); (b) the existence with
respect to any Plan of an "accumulated funding deficiency" (as defined in
Section 412 of the Code or Section 302 of ERISA), whether or not waived; (c) the
filing pursuant to Section 412(d) of the Code or Section 303(d) of ERISA of an
application for a waiver of the minimum funding standard with respect to any
Plan; (d) the

                                       6
<PAGE>

incurrence by Lessee or Guarantor of any liability under Title IV of ERISA with
respect to the termination of any Plan; (e) the receipt by Lessee or Guarantor
from the Pension Benefit Guaranty Corporation as defined in ERISA (and any
successor entity) or a plan administrator of any notice relating to an intention
to terminate any Plan or Plans or to appoint a trustee to administer any Plan;
(f) the incurrence by Lessee or Guarantor of any liability with respect to the
withdrawal or partial withdrawal from any Plan or multiemployer plan (as defined
in Section 4001(a)(3) of ERISA); or (g) the receipt by Lessee or Guarantor of
any notice, or the receipt by any multiemployer plan from Lessee or Guarantor of
any notice, concerning the imposition of Withdrawal Liability or a determination
that a multiemployer plan is, or is expected to be, insolvent or in
reorganization, within the meaning of Title IV of ERISA.

         Event of Default: The occurrence of any of the following:

         (a) Lessee fails to pay or cause to be paid the Rent when due and
payable;

         (b) Any of Lessee, Guarantor or WCG, has a petition in bankruptcy filed
against it, is adjudicated a bankrupt or has an order for relief thereunder
entered against it, or a court of competent jurisdiction enters an order or
decree appointing a receiver of Lessee, Guarantor or WCG or of the whole or
substantially all of its property, or approving a petition filed against Lessee
seeking reorganization or arrangement of Lessee under the federal bankruptcy
laws or any other applicable law or statute of the United States of America or
any state thereof, and such judgment, order or decree is not vacated or set
aside or stayed within sixty (60) days from the date of the entry thereof,
subject to the applicable provisions of the Bankruptcy Code (11 U.S.C. Section
101, et seq.) and to the provisions of Section 16.7;

         (c) Lessee, Guarantor or WCG: (i) admits in writing its inability to
pay its debts generally as they become due, (ii) files a petition in bankruptcy
or a petition to take advantage of any insolvency law, (iii) makes a general
assignment for the benefit of its creditors, (iv) consents to the appointment of
a receiver of itself or of the whole or any substantial part of its property, or
(v) files a petition or answer seeking reorganization or arrangement under the
Federal bankruptcy laws or any other applicable law or statute of the United
States of America or any state thereof, subject to the applicable provisions of
the Bankruptcy Code (11 U.S.C. Section 101, et seq.) and to the provisions of
Section 16.7;

         (d) Lessee, Guarantor or WCG, is liquidated or dissolved, or begins a
Proceeding toward liquidation or dissolution, or has filed against it a petition
or other Proceeding to cause it to be liquidated or dissolved and the Proceeding
is not dismissed within thirty (30) days thereafter, or Lessee or Guarantor in
any manner permits the sale or divestiture of substantially all of its assets;

         (e) The estate or interest of Lessee in the Leased Properties or any
part thereof is levied upon or attached in any Proceeding and the same is not
vacated or discharged within thirty (30) days thereafter (unless Lessee is in
the process of contesting such lien or attachment in good faith in accordance
with Article XII);

                                       7
<PAGE>

         (f) Any representation or warranty made by Lessee or Guarantor in the
Purchase Agreement or in the certificates delivered in connection therewith
shall prove to be incorrect in any material respect when made or deemed made,
Lessor is materially and adversely affected thereby and Lessee or Guarantor as
the case may be, fails within twenty (20) days after Notice from Lessor thereof
to cure such condition by terminating such adverse effect and making Lessor
whole for any damage suffered therefrom, or, if with due diligence such cure
cannot be effected within twenty (20) days, if Lessee has failed to commence to
cure the same within the twenty (20) days or failed thereafter to proceed
promptly and with due diligence to cure such condition and complete such cure
prior to the time that such condition causes a default in any Facility Mortgage
or any other lease to which Lessee is subject and prior to the time that the
same results in civil or criminal penalties to Lessor, Lessee, Guarantor or any
Affiliates of any of such parties or the Leased Properties;

         (g) Lessee defaults, or permits a default, under any Facility Mortgage,
related documents or obligations thereunder which default is not cured within
any applicable grace period provided for therein;

         (h) A default occurs under the Guaranty;

         (i) A Transfer occurs without the prior written consent of Lessor;

         (j) Except as otherwise provided in subsection (o) below, a default
occurs under any Material Debt when and as the same become due and payable
(subject to any applicable grace period);

         (k) Lessee fails to purchase the Leased Properties if and as required
under this Lease;

         (l) Lessee, Guarantor or WCG breaches any of the financial covenants
set forth in Article VIII hereof and the breach is not cured within a period of
thirty (30) days after the earlier to occur of (i) the Notice thereof from
Lessor, or (ii) knowledge thereof by Lessee, Guarantor or WCG;

         (m) Lessee or Guarantor fails to observe or perform any other term,
covenant or condition of this Lease and the failure is not cured by Lessee
within a period of thirty (30) days after Notice thereof from Lessor;

         (n) Lessee or Guarantor breaches any representation or warranty made by
it in this Lease;

         (o) An Event of Default (as defined in the Credit Agreement), occurs
and an acceleration of any of the Loans as defined in the Credit Agreement
results;

         (p) One or more judgments for the payment of money in an aggregate
amount in excess of $25,000,000 shall be rendered against Lessee, Guarantor or
WCG, or any

                                       8
<PAGE>

combination thereof and the same shall remain undischarged for a period of
thirty (30) consecutive days during which execution shall not be effectively
stayed, or any action shall be legally taken by a judgment creditor to attach or
levy upon any assets of Lessee, Guarantor or WCG to enforce any such judgment;

         (q) An ERISA Event shall have occurred that, in the opinion of the
Lessor, when taken together with all other ERISA Events that have occurred,
could reasonably be expected to result in liability of Lessee, Guarantor or WCG
in an aggregate amount exceeding $25,000,000 for all periods;

         (r) The Guaranty shall cease for any reason (other than the merger out
of existence of the Guarantor pursuant to a transaction permitted hereunder or
pursuant to the express terms of the Guaranty) to be in full force and effect,
or Guarantor shall so assert in writing;

         (s) A Change in Control shall occur;

         (t) Lessee or Guarantor fails to observe or perform any provisions of
Article XIII regarding insurance; or

         (u) This Lease together with the Purchase Agreement are determined not
to be a Qualifying Issuance as defined in the Credit Agreement.

         Facility: Each of the Center and the Parking Structure.

         Facility Mortgage: Any mortgage, deed of trust or other security
agreement which with the express, prior, written consent of Lessor is a lien
upon any or all of the Leased Properties, whether such lien secures an Assumed
Indebtedness or another obligation or obligations.

         Facility Mortgagee: The secured party to a Facility Mortgage.

         Financial Statement: As to WCG, for any period, a statement of earnings
and retained earnings and of changes in financial position and profit and loss
for such period, and for the period from the beginning of the fiscal year to the
end of such period, and the related balance sheet as at the end of such period,
together with the notes thereto, all in reasonable detail and setting forth in
comparative form the corresponding figures for the corresponding period in the
preceding fiscal year, and prepared in accordance with GAAP, certified to be
accurate and complete by the chief financial officer of WCG. WCG's fiscal
year-end Financial Statement shall be an audited financial report prepared by
Ernst & Young LLP or other independent certified public accountants of
recognized national standing and otherwise reasonably satisfactory to Lessor,
containing WCG's balance sheet as of the end of that year, its related profits
and losses, a statement of shareholder's equity for that year, a statement of
cash flows for that year, any management letter prepared by those certified
public accountants and such comments and financial details as are customarily
included in reports of like character and the unqualified opinion of the
certified public accountants as to the fairness of the statements therein.

         Fixtures: Collectively, all permanently affixed Equipment, machinery,
and fixtures, all as defined in Article 9 of the UCC, and other items of real
and/or personal property (excluding

                                       9
<PAGE>

Leased Personal Property and any portion of the Central Plant), including all
components thereof, now and hereafter located in, on or used in connection with,
and permanently affixed to or incorporated into the Leased Improvements,
including, without limitation, all furnaces, boilers, heaters, electrical
equipment, heating, plumbing, lighting, ventilating, refrigerating,
incineration, air and water pollution control, waste disposal, air-cooling and
air-conditioning systems and apparatus (other than individual units), sprinkler
systems and fire and theft protection equipment, towers and other devices for
the transmission of radio, television and other signals, all of which, to the
greatest extent permitted by law, are hereby deemed by the parties hereto to
constitute real estate, together with all replacements, modifications,
alterations and additions thereto.

         GAAP: Generally accepted accounting principles in the United States of
America, in effect at the time in question.

         Governmental Authority: The government of the United States of America,
any other nation or any political subdivision thereof, whether state or local,
and any agency, authority, instrumentality, regulatory body, court, central bank
or other entity exercising executive, legislative, judicial, taxing, regulatory
or administrative powers or functions of or pertaining to government.

         Guaranty: The Guaranty of even date herewith in the form attached
hereto as EXHIBIT H executed by Guarantor.

         Hazardous Materials: All explosive or radioactive substances or wastes
and all hazardous or toxic substances, wastes or other pollutants, including
petroleum or petroleum distillates, asbestos or asbestos containing materials,
polychlorinated biphenyls, radon gas, infectious or medical wastes and all other
substances or wastes of any nature regulated pursuant to any Environmental Law
as hazardous, toxic, a pollutant or a contaminant.

         Impositions: Collectively, all taxes (including, without limitation,
all capital stock and franchise taxes of Lessor and all ad valorem, sales and
use, single business, gross receipts, transaction privilege, rent or similar
taxes to the extent the same are assessed against Lessor on the basis of its
gross or net income from this Lease or the value of the Leased Properties),
assessments (including Assessments), ground rents, water, sewer or other rents
and charges, excises, tax levies, fees (including, without limitation, license,
permit, inspection, authorization and similar fees), and all other governmental
charges, in each case whether general or special, ordinary or extraordinary, or
foreseen or unforeseen, of every character in respect of the Leased Properties
or the businesses conducted thereon by Lessee and/or the Rent (including all
interest and penalties thereon), which at any time prior to, during or in
respect of the Term may be assessed or imposed on or in respect of or be a lien
upon (i) Lessor or Lessor's interest in the Leased Properties, (ii) the Leased
Properties or any part thereof or any rent therefrom or any estate, right, title
or interest therein, or (iii) any occupancy, operation, use or possession of, or
sales from, or activity conducted on, or in connection with the Leased
Properties or the leasing or use of the Leased Properties or any part thereof or
(iv) the Rent; notwithstanding the foregoing, Imposition shall not include: (i)
except as provided above, any tax imposed on Lessor's gross or net income
generally and not specifically arising in connection with the Leased Properties
(unless

                                       10
<PAGE>

such a tax is levied, assessed or imposed in lieu of a portion or all of a tax
which was included within the definition of "Imposition,") or (ii) any transfer
or other tax imposed with respect to any subsequent sale, exchange or other
disposition by Lessor of the Leased Properties or any part thereof or the
proceeds thereof.

         Insurance Requirements: All terms of any insurance policy required by
this Lease and all requirements of the issuer of any such policy.

         Interest Rate: The rate as set forth on EXHIBIT I.

         Inventory: Collectively, all of the inventory as defined in Article 9
of the UCC comprising part of the Leased Personal Property.

         Investigation: Soil and chemical tests or any other environmental
investigations, examinations or analyses.

         Judgment Date: The date on which a judgment is entered against Lessee
which establishes, without the possibility of appeal, the amount of liquidated
damages to which Lessor is entitled hereunder.

         Land: The Center Parcel and the Parking Structure Parcel.

         La Petite Lease. The term "La Petite Lease" shall mean that certain
Ground Lease with Construction by Lessee between Williams Realty Corp. (now
Williams Headquarters Building Company), as Landlord and La Petite Academy,
Inc., as Lessee, dated July 22, 1987, as amended by that certain First Amendment
to Lease Agreement dated February 28, 1989.

         La Petite Parcel. The term "La Petite Parcel" shall mean the real
property covered by the La Petite Lease.

         Lease: As defined in the Preamble.

         Lease Year: Each period of twelve (12) calendar months commencing with
the Commencement Date, and any succeeding twelve (12) month period during the
Term.

         Leased Improvements: Collectively, all buildings, structures, Fixtures
and other improvements of every kind on the Land including, but not limited to
the Center, the Parking Structure and the Skywalk, and all alleyways, sidewalks,
utility pipes, conduits and lines (on-site and off-site), parking areas and
roadways appurtenant to such buildings and structures.

         Leased Personal Property: The Category 1 FF&E, the Category 2 FF&E, and
all Personal Property leased to Lessee on the Commencement Date, and all
Personal Property that pursuant to the terms of the Lease becomes the property
of Lessor during the Term.

                                       11
<PAGE>

         Leased Property: The Land on which a Facility is located, the Leased
Improvements on such portion of the Land, the Related Rights with respect to
such portion of the Land.

         Leased Properties: All Leased Property and Leased Personal Property,
SPECIFICALLY EXCLUDING, however, the Central Plant.

         Leased Properties Trade Name: The name under which the Leased
Properties do business during the Term. The current Leased Properties Trade Name
is both "One Technology Center" and "Williams Technology Center".

         Legal Requirements: All federal, state, county, municipal and other
governmental statutes, laws, rules, orders, waivers, regulations, ordinances,
judgments, decrees and injunctions affecting the Leased Properties or any
portion thereof, Lessee's Personal Property or the construction, use or
alteration thereof, including but not limited to the Americans with Disabilities
Act, whether enacted and in force before, after or on the Commencement Date, and
including any which may (i) require repairs, modifications, alterations or
additions in or to any portion or all of the Facilities, or (ii) in any way
adversely affect the use and enjoyment thereof, and all permits, licenses and
authorizations and regulations relating thereto, and all covenants, agreements,
restrictions and Encumbrances contained in any instruments, either of record or
known to Lessee (other than Encumbrances created by Lessor without the consent
of Lessee), in force at any time during the Term.

         Lessee's Certificate: A statement in writing in substantially the form
of EXHIBIT D (with such changes thereto as may reasonably be requested by the
person relying on such certificate).

         Lessee's Personal Property: Personal Property owned or leased by Lessee
that is not included within the definition of Leased Personal Property but is
used by Lessee in the operation of the Facilities, including Personal Property
provided by Lessee in compliance with Section 6.3.

         Manager: The Person to which management of the operation of a Facility
is delegated.

         Material Adverse Change: Any event, development or circumstance that
has had or could reasonably expect to have a Material Adverse Effect.

         Material Adverse Effect: A material adverse effect on (a) the business,
assets, operations, prospects or condition, financial or otherwise, of Lessee,
Guarantor, or WCG, taken as a whole, (b) the ability of Lessee, Guarantor, or
WCG to perform any of its duties or obligations under this Lease or the Credit
Agreement, or (c) the rights of or benefits available to the Lessor under this
Lease.

                                       12
<PAGE>

         Material Debt: Any Debt (other than the financial obligations under
this Lease), of the Lessee, Guarantor, or WCG, in an aggregate principal amount
exceeding $25,000,000.00.

         Net Proceeds: All proceeds, net of any costs incurred by Lessor in
obtaining such proceeds, payable under any policy of insurance required by
Article XIII of this Lease (including any proceeds with respect to Lessee's
Personal Property that Lessee is required or elects to restore or replace
pursuant to Section 14.3) or paid by a Condemnor for the Taking of any of all or
any portion of a Leased Property.

         Notice: A notice given in accordance with Article XXXI.

         Notice of Termination: A Notice from Lessor that it is terminating this
Lease by reason of an Event of Default or otherwise as specifically set forth in
this Lease.

         Officer: The chairman of the board of directors, the president, any
vice president and the secretary of any corporation, a general partner of any
partnership, and a manager or managing member of any limited liability company.

         Officer's Certificate: If for a corporation, a certificate signed by
one or more officers of the corporation authorized to do so by the bylaws of
such corporation or a resolution of the Board of Directors thereof; if for a
partnership, limited liability company or any other kind of entity, a
certificate signed by a Person having the authority to so act on behalf of such
entity.

         Overdue Rate: On any date, the interest rate per annum, that is equal
to two percent (2%) (two hundred (200) basis points) above the Prime Rate, but
in no event greater than the maximum rate then permitted under applicable law.

         Parking Structure. The multi-story parking facility located on the
Parking Structure Parcel.

         Parking Structure Parcel. The real property more particularly described
on EXHIBIT B on which the Parking Structure is located, which includes without
limitation, the La Petite Parcel.

         Partial Taking: A taking of less than the entire fee of a Leased
Property that either (i) does not render the Leased Property Unsuitable for its
Primary Use, or (ii) renders a Leased Property Unsuitable for its Primary
Intended Use, but neither Lessor nor Lessee elects pursuant to Section 15.1
hereof to terminate this Lease.

         Payment Date: Any due date for the payment of the installments of Base
Rent or for the payment of Additional Charges or any other amount required to be
paid by Lessee hereunder.

         Permitted Encumbrances: Encumbrances listed on attached EXHIBIT E.

                                       13
<PAGE>

         Person: Any natural person, trust, partnership, corporation, joint
venture, limited liability company or other legal entity.

         Personal Property: All tangible and intangible personal property
including but not limited to machinery, equipment, furniture, furnishings,
movable walls or partitions, computers (and all associated software), trade
fixtures and other personal property (but excluding consumable inventory and
supplies owned by Lessee) used in connection with the Leased Properties,
together with all replacements, substitutions, and alterations thereof and
additions thereto including all tangible personal property acquired hereafter
used in connection with the Leased Properties, except items, if any, (i)
included within the definition of Fixtures or Leased Improvements, and (ii) any
and all components of the Central Plant.

         Plan: Any employee pension benefit plan (other than a multiemployer
plan as defined in Section 4001(a)(3) of ERISA) subject to the provisions of
Title IV of ERISA or Section 412 of the Code or Section 302 of ERISA, and in
respect of which Lessee or Guarantor is (or, if such plan were terminated, would
under Section 4069 of ERISA be deemed to be) an "employer" as defined in Section
3(5) of ERISA.

         Primary Intended Use: Multi-use office and technology facility.

         Prime Rate: On any date, an interest rate equal to the prime rate
published by the Wall Street Journal, but in no event greater than the maximum
rate then permitted under applicable law. If the Wall Street Journal ceases to
be in existence, or for any reason no longer publishes such prime rate, the
Prime Rate shall be the rate announced as its prime rate by Citibank, N.A., and
if such bank no longer exists or does not announce a prime rate at such time,
the Prime Rate shall be the rate of interest announced as its prime rate by Bank
of America, N.A.

         Proceeding: Any litigation, action, proposal or investigation by or
against any agency or entity, including without limitation Lessee and Guarantor.

         Purchase Agreement: The Purchase and Sale Agreement of even date
herewith, among Lessor, as Purchaser, Lessee, as Seller, and Guarantor, covering
the Leased Properties.

         Rate: As defined on EXHIBIT I.

         Realty: Collectively, the Land and Leased Improvements.

         Realty Base Rent: During the Realty Term, the Realty Base Rent shall be
the sum computed as set forth on EXHIBIT J.

         Realty Base Rent Interest: As defined on EXHIBIT J.

         Realty Base Rent Principal: As defined on EXHIBIT J.

                                       14
<PAGE>

         Realty Expiration Date: September 1, 2011.

         Realty Term: Ten (10) Lease Years commencing on the Commencement Date
and ending on the Realty Expiration Date.

         Regulatory Actions: Any claim, demand, notice, action or Proceeding
brought, threatened or initiated by any governmental authority in connection
with any Environmental Law, including, without limitation, any civil, criminal
and administrative Proceeding whether or not the remedy sought is costs,
damages, equitable remedies, penalties or expenses.

         Related Rights: All easements, rights-of-way and appurtenances relating
to the Land and the Leased Improvements.

         Release: The intentional or unintentional spilling, leaking, dumping,
pouring, emptying, seeping, disposing, discharging, emitting, depositing,
injecting, leaching, escaping, abandoning, or any other release or threatened
release, however defined, of any Hazardous Materials.

         Rent: Collectively, Base Rent and Additional Charges.

         Replacement Cost: The actual replacement cost of a Leased Property.
Replacement Cost shall be an amount sufficient that neither Lessor nor Lessee is
deemed to be a co-insurer of the Leased Property in question. Lessor shall have
the right from time to time, but no more frequently than once in any period of
three (3) consecutive Lease Years, to have Replacement Cost reasonably
redetermined by the all-risk property insurance company or another reputable
appraisal service, which determination shall be final and binding on the parties
hereto, and upon such determination Lessee shall forthwith increase, but not
decrease, the amount of the insurance carried pursuant to Section 13.2.1 to the
amount so determined, subject to the approval of any Facility Mortgagee. Lessee
shall pay the fee, if any, of the insurer making such determination.

         Repurchase Price: The total Base Rent remaining unpaid at the time of
repurchase of the Realty (and the Leased Personal Property, if applicable), by
the Lessee together with all accrued, unpaid Additional Charges.

         SEC: Securities and Exchange Commission.

         Skywalk: The elevated pedestrian bridge and support structure,
connecting the Parking Structure to the Center over a portion of South
Cincinnati Avenue and a portion of East First Street, Tulsa, Oklahoma, that is
approximately twenty-seven (27) feet above the driving lanes of such streets,
together with the air rights for the three (3) dimensional space within which it
is suspended.

         State: The State of Oklahoma.

                                       15
<PAGE>

         Taken: Conveyed pursuant to a Taking.

         Taking: A taking or voluntary conveyance during the Term of all or part
of a Leased Property, or any interest therein or right accruing thereto or use
thereof, as the result of, or in settlement of any condemnation or other eminent
domain Proceeding affecting the Leased Property whether or not the same shall
have actually been commenced.

         Terms: As defined in Section 1.3.

         Termination Date: The date on which this Lease terminates pursuant to a
Notice of Termination.

         Third Party Claims: Any claim, action, demand or Proceeding (other than
Regulatory Actions) howsoever based (including without limitation those based on
negligence, trespass, strict liability, nuisance, toxic tort or detriment to
health welfare or property) due to Contamination, whether or not the remedy
sought is costs, damages, penalties or expenses, brought by any person or entity
other than a governmental agency.

         Transfer: The (a) assignment, mortgaging or other encumbering of all or
any part of Lessee's interest in this Lease or in the Leased Properties, (b)
Change in Control of Lessee, Guarantor or WCG, or (c) sale, issuance or
transfer, cumulatively or in one transaction, of any interest, or the
termination of any interest, in Lessee, Guarantor or WCG, if Lessee, Guarantor
or WCG is a joint venture, partnership, limited liability company or other
association, which results in a Change of Control of such joint venture,
partnership, limited liability company or other association.

         Transferee: An assignee, subtenant or other occupant of a Leased
Property pursuant to a Transfer.

         TWC: The Williams Companies, Inc., a Delaware corporation.

         UCC: The Uniform Commercial Code as in effect in the State.

         Unsuitable for Its Primary Intended Use: A state or condition of a
Facility such that by reason of a Partial Taking, the Facility cannot be
operated on a commercially practicable basis for its Primary Intended Use,
taking into account, among other relevant factors, the number of usable square
footage permitted by applicable law and regulation in the Facility after the
Partial Taking, the square footage Taken and the estimated revenue impact of
such Partial Taking.

         WCG: Williams Communications Group, Inc., a Delaware corporation.

         Withdrawal Liability: The liability to a multiemployer plan as a result
of a complete or partial withdrawal from such multiemployer plan, as such terms
are defined in Part I of Subtitle E of Title IV of ERISA.

                                       16
<PAGE>

                                   ARTICLE III

                                      RENT

     3.1 BASE RENT; MONTHLY INSTALLMENTS. In addition to all other payments to
be made by Lessee under this Lease, Lessee shall pay Lessor the Base Rent in
lawful money of the United States of America which is legal tender for the
payment of public and private debts, in arrears, in monthly installments. The
first installment of Base Rent shall be payable on October 1, 2001, provided
however, with respect to levels two (2) and three (3) of the Center, no Realty
Base Rent shall be payable (provided however, such Realty Base Rent shall
accrue) until both such levels are completed and ready for occupancy, which
prorated amount of Realty Base Rent (2/15ths of each monthly installment of
Realty Base Rent) shall be deducted from the total Base Rent otherwise payable
under this Lease. The Realty Base Rent Interest accruing up to and including the
date upon which such levels are completed and ready for occupancy, shall be
converted to Realty Base Rent Principal on a monthly basis. Thereafter,
installments of Base Rent shall be payable on the first (1st) day of each
calendar month. Base Rent shall be paid to Lessor, or to such other Person as
Lessor from time to time may designate by Notice to Lessee, by check or wire
transfer of immediately available federal funds to the bank account designated
in writing by Lessor. If Lessor directs Lessee to pay any Base Rent or
Additional Charges to any Person other than Lessor, Lessee shall send to Lessor
simultaneously with such payment a copy of the transmittal letter or invoice and
check whereby such payment is made, or such other evidence of such payment as
Lessor may require.

     3.2 ADDITIONAL CHARGES. In addition to the Base Rent, Lessee will also pay
as and when due, all Additional Charges.

     3.3 LATE CHARGE; INTEREST. If any Rent payable to Lessor is not paid when
due, Lessee shall pay Lessor on demand, as an Additional Charge, (a) a late
charge equal to the greater of (i) two percent (2%) of the amount not paid
within five (5) days of the date when due and (ii) any and all charges,
expenses, fees or penalties imposed on Lessor by a Facility Mortgagee for late
payment, plus (b) if such Rent (including the late charge) is not paid within
ten (10) days of the date due, interest thereon at the Overdue Rate from such
tenth (10th) day until such Rent (including the late charge and interest) is
paid in full.

     3.4 NET LEASE.

                                       17
<PAGE>

          3.4.1 Absolute Obligation. The Rent shall be paid absolutely net to
     Lessor, so that this Lease shall yield to Lessor the full amount of the
     Rent payable to Lessor hereunder throughout the Term, subject only to any
     provisions of the Lease which expressly provide for adjustment or abatement
     of Rent or other charges.

          3.4.2 No Counterclaim or Cross Complaint. If Lessor commences any
     Proceeding for non-payment of Rent, Lessee will not interpose any
     counterclaim or cross complaint or similar pleading of any nature or
     description in such Proceeding unless Lessee would lose or waive such claim
     by the failure to assert it, but Lessee does not waive any rights to assert
     such claim in a separate action brought by Lessee. The covenants to pay
     Rent are independent covenants, and Lessee shall have no right to hold
     back, offset or fail to pay any Rent because of any alleged default by
     Lessor or for any other reason whatsoever.

                                   ARTICLE IV

                                   IMPOSITIONS

     4.1 PAYMENT OF IMPOSITIONS. Subject to Article XII relating to permitted
contests, Lessee will pay all Impositions at least twenty (20) days before any
fine, penalty, interest or cost is added for non-payment, and will promptly,
upon request, furnish to Lessor copies of official receipts or other
satisfactory proof evidencing such payments. If at the option of the taxpayer
any Imposition may lawfully be paid in installments, Lessee may pay the same in
the required installments provided it also pays any and all interest due thereon
as and when due.

     4.2 ADJUSTMENT OF IMPOSITIONS. Impositions imposed in respect of the
tax-fiscal period during which the Term ends shall be adjusted and prorated
between Lessor and Lessee, whether or not imposed before or after the expiration
of the Term or the earlier termination thereof, and Lessee's obligation to pay
its prorated share thereof shall survive such expiration or earlier termination.

     4.3 UTILITY CHARGES. Lessee will pay or cause to be paid when due all
charges for electricity, power, gas, oil, water and other utilities imposed upon
the Leased Properties or upon Lessor or Lessee with respect to the Leased
Properties.

     4.4 INSURANCE PREMIUMS. Lessee shall pay or cause to be paid when due all
premiums for the insurance coverage required to be maintained pursuant to
Article XIII during the Term.

     4.5 TAX RETURNS AND REFUNDS. Lessee shall prepare and file as and when
required all tax returns and reports required by governmental authorities with
respect to all Impositions. Lessor and Lessee shall each, upon request, provide
the other with such data, including without limitation cost and depreciation
records, as is maintained by the party to whom

                                       18
<PAGE>

the request is made as is necessary to prepare any required returns and reports.
If any provision of any Facility Mortgage requires deposits for payment of
Impositions, Lessee shall either pay the required deposits to Lessor monthly and
Lessor shall make the required deposits, or, if directed in writing to do so by
Lessor, Lessee shall make such deposits directly. Lessee shall be entitled to
receive and retain any refund from a taxing authority in respect of an
Imposition paid by Lessee if at the time of the refund no Event of Default has
occurred and is continuing, but if an Event of Default has occurred and is
continuing at the time of the refund, Lessee shall not be entitled to receive or
retain such refund and if and when received by Lessor such refund shall be
applied as provided in Article XVI.

                                    ARTICLE V

                            NO TERMINATION AND WAIVER

     5.1 NO TERMINATION, ABATEMENT, ETC. Lessee shall not take any action
without the consent of Lessor to modify, surrender or terminate this Lease, and
shall not seek or be entitled to any abatement, deduction, deferment or
reduction of Rent, or setoff against Rent. The respective obligations of Lessor
and Lessee shall not be affected by reason of (i) any damage to, or destruction
of, the Leased Properties or any portion thereof from whatever cause or any
Taking of the Leased Properties or any portion thereof, except as expressly set
forth herein; (ii) the lawful or unlawful prohibition of, or restriction upon,
Lessee's use of the Leased Properties, or any portion thereof, or the
interference with such use by any Person or by reason of eviction by paramount
title; (iii) any claim which Lessee has or might have against Lessor or by
reason of any default or breach of any warranty by Lessor under this Lease or
any other agreement between Lessor and Lessee, or to which Lessor and Lessee are
parties, (iv) any bankruptcy, insolvency, reorganization, composition,
readjustment, liquidation, dissolution, winding up or other Proceeding affecting
Lessor or any assignee or transferee of Lessor, or (v) any other cause whether
similar or dissimilar to any of the foregoing other than a discharge of Lessee
from any such obligations as a matter of law. Lessee hereby specifically waives
all rights, arising from any occurrence whatsoever, which may now or hereafter
be conferred upon it by law to (a) modify, surrender or terminate this Lease or
quit or surrender the Leased Properties or any portion thereof, or (b) entitle
Lessee to any abatement, reduction, suspension or deferment of the Rent or other
sums payable by Lessee hereunder except as otherwise specifically provided in
this Lease.

                                   ARTICLE VI

                             LEASE CHARACTERIZATION

     6.1 STATUS OF OWNERSHIP OF THE LEASED PROPERTIES. Lessor and Lessee agree
that to the full extent permitted by applicable tax law and GAAP, for Lessee,
this Lease shall be treated (i) as an operating lease for tax purposes, and (ii)
as a capital lease for financial purposes. Notwithstanding anything contained in
this Section 6.1 or anywhere else in this Lease to the contrary, Lessor, Lessee
and Guarantor agree that it is their intention that this Lease be treated as a
true lease for purposes of the UCC and other applicable laws of the State.

                                       19
<PAGE>

     6.2 LEASED PERSONAL PROPERTY. Lessee shall, during the Term, maintain all
of the Leased Personal Property in good order, condition and repair as shall be
necessary in order to operate the Facilities for the Primary Intended Use in
compliance with all applicable licensure and certification requirements, all
applicable Legal Requirements and Insurance Requirements, and customary industry
practice for the Primary Intended Use. If any of the Leased Personal Property
requires replacement in order to comply with the foregoing, Lessee shall replace
it with similar property of the same or better quality at Lessee's sole cost and
expense, and when such replacement property is placed in service with respect to
the Leased Properties it shall become Leased Personal Property. Lessee shall not
permit or suffer Leased Personal Property to be subject to any lien, charge,
Encumbrance, financing statement, contract of sale, equipment Lessor's interest
or the like, except for any purchase money security interest or equipment
Lessor's interest expressly approved in advance, in writing, by Lessor. Unless
Lessee purchases the Leased Properties as provided in this Lease, upon the
expiration or earlier termination of this Lease, all of Leased Personal Property
shall be surrendered to Lessor with the Leased Properties at or before the time
of the surrender of the Leased Properties in at least as good a condition as at
the Commencement Date (or, as to replacements, in at least as good a condition
as when placed in service at the Facilities) except for ordinary wear and tear.

     6.3 LESSEE'S PERSONAL PROPERTY. Lessee shall provide and maintain during
the Term such Personal Property, in addition to the Leased Personal Property, as
shall be necessary and appropriate in order to operate the Facilities for the
Primary Intended Use in compliance with all licensure and certification
requirements, in compliance with all applicable Legal Requirements and Insurance
Requirements and otherwise in accordance with customary practice in the industry
for the Primary Intended Use. Without the prior written consent of Lessor,
Lessee shall not permit or suffer Lessee's Personal Property to be subject to
any lien, charge, Encumbrance, financing statement or contract of sale or the
like. Unless Lessee purchases the Leased Properties as provided in this Lease,
upon the expiration of the Term or the earlier termination of this Lease,
without the payment of any additional consideration by Lessor, Lessee shall be
deemed to have sold, assigned, transferred and conveyed to Lessor all of
Lessee's right, title and interest in and to any of Lessee's Personal Property
that, in Lessor's reasonable judgment, is integral to the Primary Intended Use
of the Facilities (or if some other use thereof has been approved by Lessor as
required herein, such other use as is then being made by Lessee) and, as
provided in Section 34.1, Lessor shall have the option to purchase any of
Lessee's Personal Property that is not then integral to such use. Without
Lessor's prior written consent, Lessee shall not remove Lessee's Personal
Property that is in use at the expiration or earlier termination of the Term
from the Leased Properties until such option to purchase has expired or been
waived in writing by Lessor. Any of Lessee's Personal Property that is not
integral to the use of the Facilities being made by Lessee and is not purchased
by Lessor pursuant to Section 34.1 may be removed by Lessee upon the expiration
or earlier termination of this Lease, and, if not removed within twenty (20)
days following the expiration or earlier termination of this Lease, shall be
considered abandoned by Lessee and may be appropriated, sold, destroyed or
otherwise disposed of by Lessor without giving notice thereof to Lessee and
without any payment to Lessee or any obligation to account therefor. Lessee
shall reimburse Lessor for any and all expense incurred by Lessor in disposing
of any of Lessee's Personal Property that Lessee may remove but within such
twenty (20) day period fails to remove, and shall either at its own expense
restore the Leased

                                       20
<PAGE>

Properties to the condition required by Section 9.1.5, including repair of all
damage to the Leased Properties caused by the removal of any of Lessee's
Personal Property, or reimburse Lessor for any and all expense incurred by
Lessor for such restoration and repair.

                                   ARTICLE VII

                    CONDITION, USE AND ENVIRONMENTAL MATTERS

     7.1 CONDITION OF THE LEASED PROPERTIES. Lessee acknowledges that it has
inspected and otherwise has knowledge of the condition of the Leased Properties
prior to the execution and delivery of this Lease and has found the same to be
in good order and repair and satisfactory for its purposes hereunder. Lessee is
leasing the Leased Properties "as is" in their condition on the Commencement
Date. Lessee waives any claim or action against Lessor in respect of the
condition of the Leased Properties. LESSOR MAKES NO WARRANTY OR REPRESENTATION
EXPRESS OR IMPLIED, IN RESPECT OF THE LEASED PROPERTIES OR ANY PART THEREOF,
EITHER AS TO ITS FITNESS FOR USE, DESIGN OR CONDITION FOR ANY PARTICULAR USE OR
PURPOSE OR OTHERWISE AS TO THE QUALITY OF THE MATERIAL OR WORKMANSHIP THEREIN,
LATENT OR PATENT, IT BEING AGREED THAT ALL SUCH RISKS ARE TO BE BORNE BY LESSEE.
Lessee further acknowledges that throughout the Term Lessee is solely
responsible for the condition of the Leased Properties. Subject in all cases to
the provisions of Section 3.4.2, nothing contained in this Agreement including
without limitation, this Section 7, shall be deemed to inhibit, restrict or
waive any independent rights Lessee may have under the Construction Completion
Agreement.

     7.2 USE OF THE LEASED PROPERTIES. Throughout the Term, Lessee shall
continuously use the Leased Properties for the Primary Intended Use and uses
incidental thereto. Lessee shall not use the Leased Properties or any portion
thereof for any other use without the prior written consent of Lessor. No use
shall be made or permitted to be made of, or allowed in, the Leased Properties,
and no acts shall be done, which will cause the cancellation of, or be
prohibited by, any insurance policy covering the Leased Properties or any part
thereof, nor shall the Leased Properties or Lessee's Personal Property be used
for any unlawful purpose. Lessee shall not commit or suffer to be committed any
waste on the Leased Properties, or cause or permit any nuisance thereon, or
suffer or permit the Leased Properties or any portion thereof, or Lessee's
Personal Property, to be used in such a manner as (i) might reasonably tend to
impair Lessor's (or Lessee's, as the case may be) title thereto or to any
portion thereof, or (ii) may reasonably make possible a claim or claims of
adverse usage or adverse possession by the public, as such, or of implied
dedication of the Leased Properties or any portion thereof.

     7.3 CERTAIN ENVIRONMENTAL MATTERS.

          7.3.1 Prohibition Against Use of Hazardous Materials. Lessee shall not
     permit, conduct or allow on the Leased Properties, the generation,
     introduction, presence, maintenance, use, receipt, acceptance, treatment,
     manufacture, production, installation, management, storage, disposal or
     release of any Hazardous Materials except for those

                                       21
<PAGE>

     types and quantities of Hazardous Materials necessary for and ordinarily
     associated with the conduct of Lessee's business which are used in full
     compliance with all Environmental Laws.

          7.3.2 Notice of Environmental Claims, Actions or Contaminations.
     Lessee shall notify Lessor, in writing, immediately upon learning of any
     existing, pending or threatened: (a) investigation, inquiry, claim or
     action by any governmental authority in connection with any Environmental
     Laws, (b) Third Party Claims, (c) Regulatory Actions, and/or (d)
     Contamination of any portion of the Leased Properties.

          7.3.3 Costs of Remedial Actions with Respect to Environmental Matters.
     If any investigation and/or Clean-Up of any Hazardous Materials or other
     environmental condition on, under, about or with respect to a Leased
     Property is required by any Environmental Law, Lessee shall complete, at
     its own expense, such investigation and/or Clean-Up or cause any other
     Person that may be legally responsible therefore to complete such
     investigation and/or Clean-Up.

          7.3.4 Delivery of Environmental Documents. Lessee shall deliver to
     Lessor complete copies of any and all Environmental Documents that may now
     be in or at any time hereafter come into the possession of Lessee.

          7.3.5 Environmental Audit. At Lessee's expense, Lessee shall deliver
     to Lessor, an Environmental Audit from time to time, upon and within thirty
     (30) days of Lessor's request therefor, but no more than once every two (2)
     calendar years, except in the event of (i) any construction or excavation
     of, or material alteration to any portion of the Leased Properties, or (ii)
     Lessor reasonably suspects that Contamination of any portion of the Leased
     Properties has occurred or been discovered, in either case Lessor may
     thereafter request an Environmental Audit. All tests and samplings shall be
     conducted using generally accepted and scientifically valid technology and
     methodologies. Lessee shall give the engineer or environmental consultant
     conducting the Environmental Audit reasonable and complete access to the
     Leased Properties and to all records in the possession of Lessee that may
     indicate the presence (whether current or past) of a Release or threatened
     Release of any Hazardous Materials on, in, under, about and adjacent to any
     Leased Property. Lessee shall also provide the engineer or environmental
     consultant full access to and the opportunity to interview such persons as
     may be employed in connection with the Leased Properties as the engineer or
     consultant deems appropriate. However, Lessor shall not be entitled to
     request an Environmental Audit from Lessee unless (a) after the
     Commencement Date there have been changes, modifications or additions to
     Environmental Laws as applied to or affecting any of the Leased Properties;
     (b) a significant change in the condition of any of the Leased Properties
     has occurred; (c) there are fewer than six (6) months remaining in the
     Term; or (d) Lessor has another good reason for requesting such certificate
     or certificates. If the Environmental Audit discloses the presence of
     Contamination or any noncompliance with Environmental Laws, Lessee shall
     immediately perform all of Lessee's obligations hereunder with respect to
     such Hazardous Materials or noncompliance.

                                       22
<PAGE>

          7.3.6 Entry onto Leased Properties for Environmental Matters. If
     Lessee fails to provide an Environmental Audit as and when required by
     Section 7.3.5, in addition to Lessor's other remedies Lessee shall permit
     Lessor from time to time, by its employees, agents, contractors or
     representatives, to enter upon the Leased Properties for the purpose of
     conducting such Investigations as Lessor may desire, the expense of which
     shall promptly be paid or reimbursed by Lessee as an Additional Charge.
     Lessor, and its employees, agents, contractors, consultants and/or
     representatives, shall conduct any such Investigation in a manner which
     does not unreasonably interfere with Lessee's use of and operations on the
     Leased Properties (however, reasonable temporary interference with such use
     and operations is permissible if the investigation cannot otherwise be
     reasonably and inexpensively conducted). Other than in an emergency, Lessor
     shall provide Lessee with prior notice before entering any of the Leased
     Properties to conduct such Investigation, and shall provide copies of any
     reports or results to Lessee, and Lessee shall cooperate fully in such
     Investigation.

          7.3.7 Environmental Matters Upon Termination of the Lease or
     Expiration of Term. Upon the expiration or earlier termination of the Term
     of this Lease, Lessee shall cause the Leased Properties to be delivered
     free of any and all Regulatory Actions and Third Party Claims and otherwise
     in compliance with all Environmental Laws with respect thereto, and in a
     manner and condition that is reasonably required to ensure that the then
     present use, operation, leasing, development, construction, alteration,
     refinancing or sale of the Leased Property shall not be restricted by any
     environmental condition existing as of the date of such expiration or
     earlier termination of the Term.

          7.3.8 Compliance with Environmental Laws. Lessee shall comply with,
     and cause its agents, servants and employees, to comply with, and shall use
     reasonable efforts to cause each occupant and user of any of the Leased
     Properties, and the agents, servants and employees of such occupants and
     users, to comply with each and every Environmental Law applicable to
     Lessee, the Leased Properties and each such occupant or user with respect
     to the Leased Properties. Specifically, but without limitation:

               7.3.8.1 Maintenance of Licenses and Permits. Lessee shall obtain
          and maintain (and Lessee shall use reasonable efforts to cause each
          tenant, occupant and user to obtain and maintain) all permits,
          certificates, licenses and other consents and approvals required by
          any applicable Environmental Law from time to time with respect to
          Lessee, each and every part of the Leased Properties and/or the
          conduct of any business at a Facility or related thereto;

               7.3.8.2 Contamination. Lessee shall not cause, suffer or permit
          any Contamination;

               7.3.8.3 Clean-Up. If a Contamination occurs, the Lessee promptly
          shall Clean-Up and remove any Hazardous Materials or cause the
          Clean-Up and the removal of any Hazardous Materials and in any such
          case such Clean-Up and

                                       21
<PAGE>

          removal of the Hazardous Materials shall be effected to Lessor's
          reasonable satisfaction and in any event in strict compliance with and
          in accordance with the provisions of the applicable Environmental
          Laws;

               7.3.8.4 Discharge of Lien. Within twenty (20) days of the date
          any lien is imposed against the Leased Properties or any part thereof
          under any Environmental Law, Lessee shall cause such lien to be
          discharged (by payment, by bond or otherwise to Lessor's absolute
          satisfaction);

               7.3.8.5 Notification of Lessor. Within five (5) Business Days
          after receipt by Lessee of notice or discovery by Lessee of any fact
          or circumstance which might result in a breach or violation of any
          covenant or agreement, Lessee shall notify Lessor in writing of such
          fact or circumstance; and

               7.3.8.6 Requests, Orders and Notices. Within five (5) Business
          Days after receipt of any request, order or other notice relating to
          the Leased Properties under any Environmental Law, Lessee shall
          forward a copy thereof to Lessor.

          7.3.9 Environmental Related Remedies. In the event of a breach by
     Lessee beyond any applicable notice and/or grace period of its covenants
     with respect to environmental matters, Lessor may, in its sole discretion,
     do any one or more of the following (the exercise of one right or remedy
     hereunder not precluding the simultaneous or subsequent exercise of any
     other right or remedy hereunder):

               7.3.9.1 Cause a Clean-Up. Cause the Clean-Up of any Hazardous
          Materials or other environmental condition on or under the Leased
          Properties, or both, at Lessee's cost and expense; or

               7.3.9.2 Payment of Regulatory Damages. Pay on behalf of Lessee
          any damages, costs, fines or penalties imposed on Lessee or Lessor as
          a result of any Regulatory Actions; or

               7.3.9.3 Payments to Discharge Liens. On behalf of Lessee, make
          any payment or perform any other act or cause any act to be performed
          which will prevent a lien in favor of any federal, state or local
          governmental authority from attaching to the Leased Properties or
          which will cause the discharge of any lien then attached to the Leased
          Properties; or

               7.3.9.4 Payment of Third Party Damages. Pay, on behalf of Lessee,
          any damages, cost, fines or penalties imposed on Lessee as a result of
          any Third Party Claims; or

               7.3.9.5 Demand of Payment. Demand that Lessee make immediate
          payment of all of the costs of such Clean-Up and/or exercise of the
          remedies set

                                       24
<PAGE>

          forth in this Section 7.3 incurred by Lessor and not theretofore paid
          by Lessee as of the date of such demand.

          7.3.10 Environmental Indemnification. Lessee and Guarantor shall and
     do hereby indemnify, and shall defend and hold harmless Lessor, its
     principals, Officers, directors, agents, employees, parents, and Affiliates
     from each and every incurred and potential claim, cause of action, damage,
     demand, obligation, fine, laboratory fee, liability, loss, penalty,
     imposition settlement, levy, lien removal, litigation, judgment,
     Proceeding, disbursement, expense and/or cost (including without limitation
     the cost of each and every Clean-Up), however defined and of whatever kind
     or nature, known or unknown, foreseeable or unforeseeable, contingent,
     incidental, consequential or otherwise (including, but not limited to,
     attorneys' fees, consultants' fees, experts' fees and related expenses,
     capital, operating and maintenance costs, incurred in connection with (i)
     any Investigation or monitoring of site conditions, (ii) any amounts paid
     or advanced by Lessor on behalf of Lessee as set forth in this Article 7,
     and (iii) any Clean-Up required or performed by any federal, state or local
     governmental entity or performed by any other entity or person because of
     the presence of any Hazardous Materials, Release, threatened Release or any
     Contamination on, in, under or about any of the Leased Properties) which
     may be asserted against, imposed on, suffered or incurred by, each and
     every indemnitee arising out of or in any way related to, or allegedly
     arising out of or due to any environmental matter including, but not
     limited to, any one or more of the following:

               7.3.10.1 Release Damage or Liability. The presence of
          Contamination in, on, at, under, or near a Leased Property or
          migrating to a Leased Property from another location;

               7.3.10.2 Injuries. All injuries to health or safety (including
          wrongful death), or to the environment, by reason of environmental
          matters relating to the condition of or activities past or present on,
          at, in, under a Leased Property;

               7.3.10.3 Violations of Law. All violations, and alleged
          violations, of any Environmental Law relating to a Leased Property or
          any activity on, in, at, under or near a Leased Property;

               7.3.10.4 Misrepresentation. All material misrepresentations
          relating to environmental matters in any documents or materials
          furnished by Lessee to Lessor and/or its representatives in connection
          with the Lease;

               7.3.10.5 Event of Default. Each and every Event of Default
          relating to environmental matters;

               7.3.10.6 Lawsuits. Any and all lawsuits brought or threatened,
          settlements reached and governmental orders relating to any Hazardous
          Materials at, on, in, under or near a Leased Property, and all demands
          of governmental authorities, and

                                       25
<PAGE>

          all policies and requirements of Lessor's, based upon or in any way
          related to any Hazardous Materials at, on, in, under a Leased
          Property; and

               7.3.10.7 Presence of Liens. All liens imposed upon any of the
          Leased Properties in favor of any governmental entity or any person as
          a result of the presence, disposal, release or threat of release of
          Hazardous Materials at, on, in, from, or under a Leased Property.

          7.3.11 Rights Cumulative and Survival. The rights granted Lessor under
     this Section 7.3 are in addition to and not in limitation of any other
     rights or remedies available to Lessor hereunder or allowed at law or in
     equity or rights of indemnification provided to Lessor in any agreement
     pursuant to which Lessor purchased any of the Leased Properties. The
     payment and indemnification obligations set forth in this Section 7.3 shall
     survive the expiration or earlier termination of the Term of this Lease.

                                  ARTICLE VIII

             LEGAL AND INSURANCE REQUIREMENTS; ADDITIONAL COVENANTS

     8.1 COMPLIANCE WITH LEGAL AND INSURANCE REQUIREMENTS. In its use,
maintenance, operation and any alteration of the Leased Properties, Lessee, at
its expense, will promptly (i) comply with all Legal Requirements and Insurance
Requirements, whether or not compliance therewith requires structural changes in
any of the Leased Improvements (which structural changes shall be subject to
Lessor's prior written approval, which approval shall not be unreasonably
withheld or delayed) or interferes with or prevents the use and enjoyment of the
Leased Properties, and (ii) procure, maintain and comply with all licenses, and
other authorizations required for the use of the Leased Properties and Lessee's
Personal Property then being made, and for the proper erection, installation,
operation and maintenance of the Leased Properties or any part thereof. The
judgment of any court of competent jurisdiction, or the admission of Lessee in
any action or Proceeding against Lessee, whether or not Lessor is a party
thereto, that Lessee has violated any such Legal Requirements or Insurance
Requirements shall be conclusive of that fact as between Lessor and Lessee.

     8.2 CERTAIN COVENANTS.

          8.2.1 Existence; Conduct of Business. Lessee, Guarantor, and WCG each
     will (i) continue to engage in business of the same general type as now
     conducted and (ii) do or cause to be done all things necessary to preserve,
     renew and keep in full force and effect its legal existence and the rights,
     licenses, permits, privileges, franchises, patents, copyrights, trademarks
     and trade names material to the conduct of its business.

                                       26
<PAGE>

          8.2.2 Payment of Obligations. Lessee, Guarantor and WCG each (i) will
     pay its Debt and other material obligations, including tax liabilities,
     before the same shall become delinquent or in default, except where (a) the
     validity or amount thereof is being contested in good faith by appropriate
     legal process, (b) has set aside on its books adequate reserves with
     respect thereto in accordance with GAAP, (c) such contest effectively
     suspends collection of the contested obligation and the enforcement of any
     Encumbrance securing such obligation and (d) the failure to make payment
     pending such contest could not reasonably be expected to result in a
     Material Adverse Effect and (ii) shall not breach, in any material respect,
     or permit to exist any material default under, the terms of any material
     lease, commitment, contract, instrument or obligation to which it is a
     party, or by which its properties or assets are bound, except where the
     failure to do the foregoing would not in the aggregate have a Material
     Adverse Effect.

          8.2.3 Maintenance of Properties. Lessee, Guarantor, and WCG each will
     keep and maintain all property material to the conduct of its business in
     good working order and condition, ordinary wear and tear excepted.

          8.2.4 Insurance. Lessee, Guarantor, and WCG each will maintain, with
     financially sound and reputable insurance companies, insurance in such
     amounts and against such risks as are customarily maintained by companies
     engaged in the same or similar businesses operating in the same or similar
     locations.

          8.2.5 Casualty and Condemnation. The Lessee will furnish to Lessor
     prompt written notice of any casualty or other insured damage to any
     portion of any of Guarantor's property or assets or the commencement of any
     action or Proceeding for the taking of any of Guarantor's property or
     assets or any part thereof or interest therein under power of eminent
     domain or by condemnation or similar Proceeding (in each case with a value
     in excess of $10,000,000).

          8.2.6 Books and Records; Inspection and Audit Rights. Lessee,
     Guarantor, and WCG each will keep proper books of record and account in
     which materially full, true and correct entries are made of all dealings
     and transactions in relation to its business and activities. Lessee,
     Guarantor, and WCG each will permit any representatives designated by the
     Lessor at the expense of Lessor, or, if an Event of Default shall have
     occurred and be continuing, at the expense of the Lessee, upon reasonable
     prior notice, to visit and inspect its properties, to examine and make
     extracts from its books and records, and to discuss its affairs, finances
     and condition with its officers and independent accountants, all at such
     reasonable times and as often as reasonably requested.

          8.2.7 Compliance with Laws. Lessee, Guarantor, and WCG each will
     comply with all laws, rules, regulations and orders of any Governmental
     Authority applicable to it or its property (including, without limitation,
     Environmental Laws and ERISA and the rules and regulations thereunder),
     except where the necessity of compliance therewith is contested in good
     faith by appropriate action and such failure to comply, individually or in
     the aggregate, could not reasonably be expected to result in a Material
     Adverse Effect.

                                       27
<PAGE>

          8.2.8 Further Assurances. At any time and from time to time, Lessee
     and Guarantor each will execute any and all further documents, financing
     statements, agreements and instruments, and take all such further actions
     (including the filing and recording of financing statements, fixture
     filings, mortgages, deeds of trust and other documents), which may be
     required under any applicable law, or which the Lessor may reasonably
     request, to effectuate the transactions contemplated by this Lease or to
     grant, preserve, protect or perfect the Encumbrances created or intended to
     be created in connection with this Lease or any of the other documents
     contemplated herein, required to be in effect or the validity or priority
     of any such Encumbrance, all at the expense of Lessee and Guarantor. Lessee
     and Guarantor also agree to provide to Lessor, from time to time upon
     request, evidence reasonably satisfactory to Lessor as to the perfection
     and priority of the Encumbrance created or intended to be created in
     connection with this Lease or any of the other documents contemplated
     herein.

     8.3 CERTAIN NEGATIVE COVENANTS.

          8.3.1 No Other Debt. Lessee shall not, directly or indirectly, incur
     or otherwise become liable for any Debt or obligation to pay money to any
     Person other than to (i) Lessor pursuant to this Lease and (ii) lessors of
     leased equipment used in the operation of the Facilities.

          8.3.2 Limitation of Distributions. In or with respect to any Lease
     Year, Lessee shall not pay or distribute to its shareholders or any
     Affiliate in the form of dividends, fees for any services or reimbursements
     for shareholder expenditures or overhead on behalf of Lessee or to its
     Affiliates.

          8.3.3 Pledge or Encumber Assets. Lessee shall not pledge or otherwise
     encumber any of its assets, other than leased equipment used in the
     operation of the Facilities and liens on assets permitted under Section
     11.1.

          8.3.4 Guarantees Prohibited. Lessee shall not guarantee any
     indebtedness of any Person (other than the guarantee of the indebtedness
     under the Credit Agreement).

          8.3.5 Encumbrances. Neither Lessee nor Guarantor will create, incur,
     assume or permit to exist any Encumbrance on any property or asset now
     owned or hereafter acquired by it, or assign or sell any income or revenues
     or rights in respect of any thereof, except for any Permitted Encumbrances
     or Encumbrances created in connection with or specifically contemplated by
     this Lease or permitted by the Credit Agreement.

          8.3.6 Fundamental Changes. Neither Lessee, Guarantor nor WCG will
     merge into or consolidate with any other Person, or permit any other Person
     to merge into or consolidate with it, or liquidate or dissolve, except
     that, if at the time thereof and immediately after giving effect thereto no
     Event of Default shall have occurred and be continuing (i) any Person may
     merge into the Lessee in a transaction in which the Lessee is the surviving
     entity, provided that any such merger involving a Person that is not

                                       28
<PAGE>

     wholly owned by either Guarantor or WCG immediately prior to such merger
     shall not be permitted, and (ii) any person may merge into the Guarantor or
     WCG in a transaction in which the Guarantor or WCG, respectively, is the
     surviving corporation.

          8.3.7 Other Material Agreements. Lessee shall not (i) enter into any
     other material agreement relating to any portion of the Leased Properties,
     or (ii) if entered into with Lessor's consent, thereafter, amend, modify,
     renew, replace or otherwise change the terms of any such material agreement
     without the prior written consent of Lessor. For purposes of this Section
     8.3.7, a "material agreement" shall mean any agreement or commitment which
     requires total payments by Lessee in excess of $1,500,000.00, or
     accumulated annual payments in excess of $500,000.00.

     8.4 ADDITIONAL FINANCIAL COVENANTS.

          8.4.1 Certain Definitions. For purposes of this Section 8.4.1,
     capitalized terms not otherwise specifically defined in this Lease, shall
     have the meanings described for such capitalized terms as contained in the
     Credit Agreement (and capitalized terms contained within such definitions
     as set forth in the Credit Agreement shall similarly have the meanings
     described for such capitalized terms therein). Lessee shall provide copies
     of any amendments or restatements or waivers to the Credit Agreement to
     Lessor within five (5) days of execution thereof. Such amendments or
     restatements or waivers shall automatically become a part hereof.

          8.4.2 Total Net Debt to Contributed Capital Ratio. The Total Net Debt
     to Contributed Capital ratio shall at no time prior to January 1, 2002
     exceed .65 to 1.00.

          8.4.3 Minimum EBITDA. The amount equal to (i) EBITDA for the period
     of four (4) fiscal quarters ending during any period set forth below plus
     (ii) ADP Interest Expense for such period minus (iii) gains for such period
     attributable to Dark Fiber and Capacity Dispositions plus (iv) Dark Fiber
     and Capacity Proceeds for such period shall not be less than the amount set
     forth below opposite such period:

<Table>
<Caption>
PERIOD                                                AMOUNT
------                                                ------

<S>                                                   <C>
January 1, 2001-March 31, 2001                        $200,000,000
April 1, 2001-June 30, 2001                           $300,000,000
July 1, 2001-September 30, 2001                       $350,000,000
October 1, 2001-December 31, 2001                     $350,000,000
</Table>

          8.4.4 Total Leverage Ratio. (a) The Total Leverage Ratio during any
     period set forth below shall not exceed the ratio set forth below opposite
     such period:

<Table>
<Caption>
                                                      TOTAL
PERIOD                                                LEVERAGE RATIO
------                                                --------------

<S>                                                   <C>
March 31, 2002-December 30, 2002                      12.50:1.00
December 31, 2002-December 30, 2003                   9.50:1.00
</Table>

                                       29
<PAGE>

<Table>
<Caption>
                                                      TOTAL
PERIOD                                                LEVERAGE RATIO
------                                                --------------

<S>                                                   <C>
December 31, 2003 and thereafter                      4.00:1.00
</Table>

          8.4.5 Senior Leverage Ratio. The Senior Leverage Ratio during any
     period set forth below shall not exceed the ratio set forth below opposite
     such period:

<Table>
<Caption>
                                                      SENIOR
PERIOD                                                LEVERAGE RATIO
------                                                --------------

<S>                                                   <C>
March 31, 2002-December 30, 2002                      5.25:1.00
December 31, 2002-December 30, 2003                   3.25:1.00
December 31, 2003 and thereafter                      2.50:1.00
</Table>

          8.4.6 Interest Coverage Ratio . The Interest Coverage Ratio for any
     period of four (4) consecutive fiscal quarters ending during any period set
     forth below shall not be less than the ratio set forth below opposite such
     period:

<Table>
<Caption>
                                                     INTEREST
PERIOD                                               COVERAGE RATIO
------                                               --------------

<S>                                                  <C>
June 30, 2002-June 29, 2003                          1.00:1.00
June 30, 2003-December 30, 2003                      1.50:1.00
December 31, 2003 and thereafter                     2.00:1.00
</Table>

                                   ARTICLE IX

                                   MAINTENANCE

     9.1 MAINTENANCE AND REPAIR.

          9.1.1 Status and Quality. Lessee, at its expense, will keep or cause
     to be kept, the Leased Properties, and all landscaping, private roadways,
     sidewalks and curbs appurtenant thereto which are under Lessee's control
     and Lessee's Personal Property in good order and repair, whether or not the
     need for such repairs arises out of Lessee's use, any prior use, the
     elements or the age of the Leased Properties or any portion thereof, or any
     cause whatsoever except the act or negligence of Lessor, and with
     reasonable promptness shall make all necessary and appropriate repairs
     thereto of every kind and nature, whether interior or exterior, structural
     or non-structural, ordinary or extraordinary, foreseen or unforeseen or
     arising by reason of a condition existing prior to the Commencement Date
     (concealed or otherwise). Lessee shall at all times maintain, operate and
     otherwise manage the Leased Properties on a basis and in a manner
     consistent with the higher of that (i) customarily applied to Class A
     commercial office buildings in the vicinity of the City of Tulsa, Oklahoma,
     or (ii) utilized by Lessor in the management of Lessor's facilities
     adjacent to the Center. All repairs shall, to the extent reasonably

                                       30
<PAGE>

     achievable, be at least equivalent in quality to the original work or the
     property to be repaired shall be replaced. Lessee will not take or omit to
     take any action the taking or omission of which might materially impair the
     value or the usefulness of the Leased Properties or any parts thereof for
     the Primary Intended Use.

          9.1.2 No Liability of Lessor. Lessor shall not under any circumstances
     be required to maintain, build or rebuild any improvements on the Leased
     Properties (or any private roadways, sidewalks or curbs appurtenant
     thereto), or to make any repairs, replacements, alterations, restorations
     or renewals of any nature or description to the Leased Properties, whether
     ordinary or extraordinary, structural or non-structural, foreseen or
     unforeseen, or upon any adjoining property, whether to provide lateral or
     other support or abate a nuisance, or otherwise, or to make any expenditure
     whatsoever with respect thereto, in connection with this Lease. Lessee
     hereby waives, to the extent permitted by law, the right to make repairs at
     the expense of Lessor pursuant to any law in effect at the time of the
     execution of this Lease or hereafter enacted.

          9.1.3 Contracting with Third Parties. Nothing contained in this Lease
     shall be construed as (i) constituting the consent or request of Lessor,
     expressed or implied, to any contractor, subcontractor, laborer,
     materialmen or vendor to or for the performance of any labor or services or
     the furnishing of any materials or other property for the construction,
     alteration, addition, repair or demolition of or to any Leased Property or
     any part thereof, or (ii) giving Lessee any right, power or permission to
     contract for or permit the performance of any labor or services or the
     furnishing of any materials or other property in such fashion as would
     permit the making of any claim against Lessor in respect thereof or to make
     any agreement that may create, or in any way be the basis for any right,
     title, interest, lien, claim or other Encumbrance upon the estate of Lessor
     in the Leased Properties, or any portion thereof. Lessor shall have the
     right to give, record and post, as appropriate, notices of
     non-responsibility under any mechanics' and construction lien laws now or
     hereafter existing.

          9.1.4 Replacements. Lessee (i) shall promptly replace any of the
     Leased Improvements or Leased Personal Property which become worn out,
     obsolete or unusable or unavailable for the purpose for which intended, and
     (ii) in Lessee's reasonable judgment, may acquire a substitute for any item
     or items of Leased Personal Property which is of higher or better quality,
     performance or function than the item for which it is substituted. All
     replacements shall have a value and utility at least equal to that of the
     items replaced and shall become part of the Leased Properties immediately
     upon their acquisition by Lessee. Upon Lessor's request, Lessee shall
     promptly execute and deliver to Lessor a bill of sale or other instrument
     establishing Lessor's lien-free ownership of such replacements. Lessee
     shall promptly repair all damage to the Leased Properties incurred in the
     course of such replacement.

          9.1.5 Vacation and Surrender. Lessee will, upon the expiration or
     prior termination of the Term, vacate and surrender the Leased Properties
     to Lessor in the condition in which they were originally received from
     Lessor, in good operating condition,

                                       31
<PAGE>

     ordinary wear and tear excepted, except as repaired, rebuilt, restored,
     altered or added to as permitted or required by the provisions of this
     Lease.

     9.2 ENCROACHMENTS; RESTRICTIONS. ETC. If, at any time, any of the Leased
Improvements are alleged to encroach upon any property, street or right of way
adjacent to a Leased Property, or to violate any restrictive covenant, or to
impair the rights of others under any easement or right of way, Lessee shall
promptly settle such allegations or take such other lawful action as may be
necessary in order to be able to continue the use of a Leased Property for the
Primary Intended Use substantially in the manner and to the extent such Leased
Property was being used at the time of the assertion of such violation,
impairment or encroachment, provided, however, that no such action shall violate
any other provision of this Lease and any alteration of a Leased Property must
be made in conformity with the applicable requirements of Article X. Lessee
shall not have any claim against Lessor or offset against any of Lessee's
obligations under this lease with respect to any such violation, impairment or
encroachment.

                                    ARTICLE X

                            ALTERATIONS AND ADDITIONS

     10.1 Construction of Alterations and Additions to the Leased Properties.
Lessee shall not (a) make or permit to be made any structural alterations,
improvements or additions of or to the Leased Properties or any part thereof, or
(b) materially alter the plumbing, HVAC or electrical systems thereon or (c)
make any other alterations, improvements or additions the cost of which exceeds
(i) Two Hundred Thousand Dollars ($200,000.00), per alteration, improvement or
addition, or (ii) One Million Dollars ($1,000,000.00), in any Lease Year, unless
and until Lessee has (d) caused complete plans and specifications therefor to
have been prepared by a licensed architect and submitted to Lessor at least
ninety (90) Business Days before the planned start of construction thereof, (e)
obtained Lessor's written approval thereof and if required, the approval of any
Facility Mortgagee, and (f) if required to do so by Lessor, provided Lessor with
reasonable assurance of the payment of the cost of any such alterations,
improvements or additions, in the form of a bond, letter of credit or cash
deposit. If Lessor requires a deposit, Lessor shall retain and disburse the
amount deposited in the same manner as is provided for insurance proceeds in
Section 14.6. If the deposit is reasonably determined by Lessor at any time to
be insufficient for the completion of the alteration, improvement or addition,
Lessee shall immediately increase the deposit to the amount reasonably required
by Lessor. Lessee shall be responsible for the completion of such improvements
in accordance with the plans and specifications approved by Lessor, and shall
promptly correct any failure with respect thereto.

          10.1.1 Lessor's Approval Not Required. Alterations and improvements
     not falling within the categories described in Section 10.1 may be made by
     Lessee without the prior approval of Lessor, (i) but only in the event any
     such alternatives or improvements do not result in a material reduction in
     Lessor's opinion, in the value of the Leased Properties, and (ii) Lessee
     shall give Lessor at least thirty (30) days prior written Notice of any
     such alterations and improvements in each and every case.

                                       32
<PAGE>

          10.1.2 Quality of Work. All alterations, improvements and additions
     shall be constructed in a first class, workmanlike manner, in compliance
     with all Insurance Requirements and Legal Requirements, be in keeping with
     the character of the Leased Properties and the area in which the Leased
     Properties are located and be designed and constructed so that the value of
     the Leased Properties will not be diminished or and that the Primary
     Intended Use of the Leased Properties will not be changed. All
     improvements, alterations and additions shall immediately become a part of
     the Leased Properties.

          10.1.3 No Claim Against Lessor. Lessee shall have no claim against
     Lessor at any time in respect of the cost or value of any such improvement,
     alteration or addition. There shall be no adjustment in the Rent by reason
     of any such improvement, alteration or addition. With Lessor's consent,
     expenditures made by Lessee pursuant to this Article X may be included as
     capital expenditures for purposes of inclusion in the capital expenditures
     budget for the Facilities and for measuring compliance with the obligations
     of Lessee set forth in Section 8.2.

          10.1.4 Asbestos - Containing Material. In connection with any
     alteration which involves the removal, demolition or disturbance of any
     asbestos-containing material, Lessee shall cause to be prepared at its
     expense a full asbestos assessment applicable to such alteration, and shall
     carry out such asbestos monitoring and maintenance program as shall
     reasonably be required thereafter in light of the results of such a
     assessment.

                                   ARTICLE XI

                                      LIENS

     11.1 LIENS. Without the consent of Lessor or as expressly permitted
elsewhere herein, Lessee will not directly or indirectly create or allow to
remain and will promptly discharge at its expense any lien, Encumbrance,
attachment, title retention agreement or claim upon the Leased Properties, and
any attachment, levy, claim or Encumbrance in respect of the Rent, except for
(i) Permitted Encumbrances, (ii) liens of mechanics, laborers, materialmen,
suppliers or vendors for sums not yet due, and (iii) liens created by the
wrongful acts or negligence of Lessor.

                                   ARTICLE XII

                         PERMITTED CONTESTS AND DEPOSITS

     12.1 PERMITTED CONTESTS. Lessee, on its own or on Lessor's behalf (or in
Lessor's name), but at Lessee's sole cost and expense, shall have the right to
contest, by an appropriate legal Proceeding conducted in good faith and with due
diligence, the amount or validity of any Imposition, Legal Requirement or
Insurance Requirement or Claim, provided (a) prior Notice of such contest is
given to Lessor, (b) the Leased Properties would not be in any danger of being
sold, uninsured or underinsured, forfeited or attached as a result of such
contest, and there is no risk to Lessor of a loss of or interruption in the
payment of, Rent, (c) in the case of

                                       33
<PAGE>

an unpaid Imposition or Claim, collection thereof is suspended during the
pendency of such contest, (d) in the case of a contest of a Legal Requirement,
compliance may legally be delayed pending such contest. Upon request of Lessor,
Lessee shall deposit funds or assure Lessor in some other manner reasonably
satisfactory to Lessor that a contested Imposition or Claim, together with
interest and penalties, if any, thereon, and any and all costs for which Lessee
is responsible will be paid if and when required upon the conclusion of such
contest. Lessee shall defend, indemnify and save harmless Lessor from all costs
or expenses arising out of or in connection with any such contest, including but
not limited to attorneys' fees. If at any time Lessor reasonably determines that
payment of any Imposition or Claim, or compliance with any Legal or Insurance
Requirement being contested by Lessee is necessary in order to prevent loss of
any of the Leased Properties or Rent or civil or criminal penalties or other
damage, upon such prior Notice to Lessee as is reasonable in the circumstances
Lessor may pay such amount, require Lessee to comply with such Legal or
Insurance Requirement or take such other action as it may deem necessary to
prevent such loss or damage. If reasonably necessary, upon Lessee's written
request Lessor, at Lessee's expense, shall cooperate with Lessee in a permitted
contest, provided Lessee upon demand reimburses Lessor for Lessor's costs
incurred in cooperating with Lessee in such contest.

                                  ARTICLE XIII

                                    INSURANCE

     13.1 GENERAL INSURANCE REQUIREMENTS. Lessee will carry or cause to be
carried and maintained in force throughout the entire Term (except as
specifically noted to the contrary) insurance as described in Sections 13.1.1
through 13.1.5, with insurance companies and deductibles/retentions reasonably
acceptable to Lessor. The limits set forth below are minimum limits and will not
be construed to limit Lessee's liability. All costs and deductible amounts will
be for the sole account of the Lessee.

          13.1.1 Worker's Compensation Insurance. Workers' compensation
     insurance complying with the laws of the State or States having
     jurisdiction over each employee, whether or not Lessee is required by such
     laws to maintain such insurance, and Employer's Liability with limits of
     $1,000,000 each accident, $1,000,000 disease each employee, and $1,000,000
     disease policy limit, provided however, in lieu of such insurance, Lessee
     may become a qualified self insured for such coverage, in which event such
     coverage shall not be required unless Lessee loses its status as a
     qualified self insured.

          13.1.2 Commercial General Liability Insurance. Commercial or
     Comprehensive general liability insurance on an occurrence form with a
     combined single limit of $1,000,000 each occurrence, and annual aggregates
     of $1,000,000, for bodily injury and property damage, including coverage
     for premises-operations, blanket contractual liability, broad form property
     damage, personal injury liability, independent contractors,

                                       34
<PAGE>

     products/completed operations, sudden and accidental pollution and
     explosion, collapse and underground.

          13.1.3 Automobile Liability. Automobile Liability insurance with a
     combined single limit of $1,000,000 each occurrence for bodily injury and
     property damage to include coverage for all owned, non-owned, and hired
     vehicles.

          13.1.4 Excess Liability Insurance. Excess or Umbrella Liability
     insurance with a combined single limit of $25,000,000 each occurrence, and
     annual aggregates of $25,000,000, for bodily injury and property damage
     covering excess of Employer's Liability and the insurance described in
     13.1.2 and 13.1.3 above.

          13.1.5 Property Insurance. From and after the date upon which Lessor
     is no longer responsible to carry such coverage under the Construction
     Completion Agreement, All-Risk Property insurance providing for the full
     replacement cost of all property located in or on the Leased Properties,
     including Leased Personal Property and Lessee's Personal Property. This
     policy shall include coverage for earthquake, flood, and windstorm. The
     policy shall also include business interruption insurance, if due to a
     covered loss, covering the Base Rent due Lessor for a period of no less
     than twelve (12) months. Lessor will be the sole loss payee as required by
     Article XIV. So long as no Event of Default is then in existence, Lessor
     shall make available to Lessee, any proceeds of business interruption
     insurance remaining after the payment of all accrued Rent, within thirty
     (30) days of Lessor's actual receipt of such proceeds, in good funds.

          13.1.6 Status of Insurance Company. Irrespective of the insurance
     requirements above, the insolvency, bankruptcy, or failure of any such
     insurance company providing insurance for Lessee, or the failure of any
     such insurance company to pay claims that occur will not be held to waive
     any of the provisions hereof.

          13.1.7 Waiver of Subrogation. In each of the above described policies,
     Lessee agrees to waive and will require its insurers to waive any rights of
     subrogation or recovery they may have against Lessor, its parent,
     subsidiary or affiliated companies. Lessor will have no liability to Lessee
     for any damage or destruction of any portion of the Leased Properties or
     any of Lessee's Personal Property.

          13.1.8 Additional Insureds. Under the insurance policies described
     hereinabove (except in Section 13.1.1), Lessor, its parent, subsidiary and
     Affiliates and will be named as additional insureds with respect to the
     policies listed in Section 13.1.2 through 13.1.4, and as sole loss payees
     with respect to the policy listed in Section 13.1.5 as their interests
     appear. This insurance will be primary over any other insurance maintained
     by Lessor, its parent, subsidiary or Affiliates. All policies shall provide
     a severability of interests clause.

          13.1.9 Non-Renewal. Non-renewal or cancellation of policies described
     above, will be effective only after written notice is received by Lessor
     from the insurance company sixty (60) days in advance of any such
     non-renewal or cancellation. Prior to

                                       35
<PAGE>

     commencing the Lease hereunder, Lessee will deliver to Lessor certificates
     of insurance evidencing the existence of the insurance and endorsements
     required above.

          13.1.10 Original or Certified Copies. In the event of a loss or claim
     arising out of or in connection with this contract, Lessee agrees, upon
     request of Lessor, to submit the original or a certified copy of its
     insurance policies for inspection by Lessor.

     13.2 PREMIUM DEPOSITS. If any provision of a Facility Mortgage requires
deposits of premiums for insurance to be made with the Facility Mortgagee,
Lessee shall pay to Lessor monthly the amounts required and Lessor shall
transfer such amounts to the Facility Mortgagee, unless, pursuant to written
direction by Lessor, Lessee makes such deposits directly with the Facility
Mortgagee.

     13.3 INCREASE IN LIMITS. If from time to time Lessor determines, in the
exercise of its reasonable business judgment, that the limits of the personal
injury or property damage - public liability insurance then being carried are
insufficient, upon Notice from Lessor Lessee shall cause such limits to be
increased to the level specified in such Notice until further increase pursuant
to the provisions of this Section.

     13.4 BLANKET POLICY. Any insurance required by this Lease may be provided
by so called blanket policies of insurance carried by Lessee, provided, however,
that the coverage afforded Lessor thereby may not thereby be less than or
materially different from that which would be provided by a separate policies
meeting the requirements of this Lease, and provided further that such policies
meet the requirements of all Facility Mortgages.

     13.5 COPIES OF POLICIES; CERTIFICATES. Copies of the policies of insurance
required by this Lease and certificates thereof shall be delivered to Lessor not
less than thirty (30) days prior to their effective date (and, with respect to
any renewal policy, not less than twenty (20) days prior to the expiration of
the existing policy), and in the event of the failure of Lessee either to carry
the required insurance or pay the premiums therefor, or to deliver copies of
policies or certificates to Lessor as required, Lessor shall be entitled, but
shall have no obligation, to obtain such insurance and pay the premiums therefor
when due, which premiums shall be repayable to Lessor upon written demand
therefor as Additional Charges.

                                   ARTICLE XIV

                       DISBURSEMENT OF INSURANCE PROCEEDS

     14.1 INSURANCE PROCEEDS. Net Proceeds shall be paid to Lessor and held,
disbursed or retained by Lessor as provided herein.

          14.1.1 Proceeds of All-Risk Property Insurance. If the Net Proceeds
     are less than the Approval Threshold, and no Event of Default has occurred
     and is continuing, Lessor shall pay the Net Proceeds to Lessee promptly
     upon Lessee's completion of the restoration of the damaged or destroyed
     Leased Property. If the Net Proceeds equal or exceed the

                                       36
<PAGE>

     Approval Threshold, and no Event of Default has occurred and is continuing,
     the Net Proceeds shall be made available for restoration or repair as
     provided in Section 14.6. Within fifteen (15) days of the receipt of the
     Net Proceeds of All-Risk Insurance, Lessor shall determine in its
     reasonable judgment, as to the portion thereof, if any, attributable to the
     Lessee's Personal Property that Lessee is not required and does not elect
     to restore or replace, and the portion so determined attributable to the
     Lessee's Personal Property that Lessee is not required and does not elect
     to restore or replace shall be paid to Lessee.

     14.2 RESTORATION IN THE EVENT OF DAMAGE OR DESTRUCTION. If all or any
portion of the Leased Properties is damaged by fire or other casualty, Lessee
shall (a) give Lessor Notice of such damage or destruction within five (5)
Business Days of the occurrence thereof, (b) within thirty (30) Business Days of
the occurrence commence the restoration of the Leased Properties and (c)
thereafter diligently proceed to complete such restoration to substantially the
same (or better) condition as the Leased Properties were in immediately prior to
the damage or destruction as quickly as is reasonably possible, but in any event
within one hundred eighty (180) days of the occurrence. Regardless of the
anticipated cost thereof, if the restoration of a Leased Property requires any
modification of structural elements, prior to commencing such modification
Lessee shall obtain Lessor's written approval of the plans and specifications
therefor.

     14.3 RESTORATION OF LESSEE'S PROPERTY. If Lessee is required to restore the
Leased Properties, Lessee shall also concurrently restore any of Lessee's
Personal Property that is integral to the Primary Intended Use of the Leased
Properties at the time of the damage or destruction.

     14.4 NO ABATEMENT OF RENT. Absent termination of this Lease as provided
herein, there shall be no abatement of Rent by reason of any damage to or the
partial or total destruction of any portion of the Leased Properties.

     14.5 WAIVER. Except as provided elsewhere in this Lease, Lessee hereby
waives any statutory or common law rights of termination which may arise by
reason of any damage to or destruction of the Leased Properties.

     14.6 DISBURSEMENT OF INSURANCE PROCEEDS EQUAL TO OR GREATER THAN THE
APPROVAL THRESHOLD. If Lessee restores or repairs the Leased Properties pursuant
to this Article XIV, and if the Net Proceeds equal or exceed the Approval
Threshold, the restoration or repair and disbursement of funds to Lessee shall
be in accordance with the following procedures:

          14.6.1 Plans and Specifications. The restoration or repair work shall
     be done pursuant to plans and specifications approved by Lessor and a
     certified construction cost statement, to be obtained by Lessee from a
     contractor reasonably acceptable to Lessor, showing the total cost of the
     restoration or repair; to the extent the cost exceeds the Net Proceeds,
     Lessee shall deposit with Lessor the amount of the excess cost, and Lessor
     shall

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<PAGE>

     disburse the funds so deposited in payment of the costs of restoration or
     repair before any disbursement of Net Proceeds.

          14.6.2 Construction Funds. Construction Funds shall be made available
     to Lessee upon request, no more frequently than monthly, as the restoration
     and repair work progresses, subject to a ten (10%) percent holdback,
     pursuant to certificates of an architect selected by Lessee that, in the
     judgment of Lessor, reasonably exercised, is highly qualified in the design
     and construction of the type of Facility being repaired and is otherwise
     reasonably acceptable to Lessor, which certificates must be in form and
     substance reasonably acceptable to Lessor.

          14.6.3 Lien Waivers. After the first disbursement to Lessee, sworn
     statements and lien waivers in an amount at least equal to the amount of
     Construction Funds previously paid to Lessee shall be delivered to Lessor
     from all contractors, subcontractors and material suppliers covering all
     labor and materials furnished through the date of the previous
     disbursement.

          14.6.4 Progress of Work. Lessee shall deliver to Lessor such other
     evidence as Lessor may reasonably request from time to time during the
     course of the restoration and repair, as to the progress of the work,
     compliance with the approved plans and specifications, the cost of
     restoration and repair and the total amount needed to complete the
     restoration and repair, and showing that there are no liens against the
     Leased Properties arising in connection with the restoration and repair and
     that the cost of the restoration and repair at least equals the total
     amount of Construction Funds then disbursed to Lessee hereunder.

          14.6.5 Inadequacy of Construction Funds. If the Construction Funds are
     at any time determined by Lessor to be inadequate for payment in full of
     all labor and materials for the restoration and repair, Lessee shall
     immediately pay the amount of the deficiency to Lessor to be held and
     disbursed as Construction Funds prior to the disbursement of any other
     Construction Funds then held by Lessor.

          14.6.6 Disbursement. The Construction Funds may be disbursed by Lessor
     to Lessee or to the persons entitled to receive payment thereof from
     Lessee, and such disbursement in either case may be made directly or
     through a third party escrow agent, such as, but not limited to, a title
     insurance company, or its agent, all as Lessor may determine in its sole
     discretion. Provided Lessee is not in default hereunder, any excess
     Construction Funds shall be paid to Lessee upon completion of the
     restoration or repair.

          14.6.7 Lessee Default. If Lessee at any time fails to promptly and
     fully perform the conditions and covenants set out hereinabove in this
     Section 14.6, and the failure is not corrected within ten (10) days of
     written Notice thereof, or if during the restoration or repair an Event of
     Default occurs hereunder, Lessor may, at its option, immediately cease
     making any further payments to Lessee for the restoration and repair.

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<PAGE>

          14.6.8 Lessor Reimbursement. Lessor may reimburse itself out of the
     Construction Funds for its reasonable expenses incurred in administering
     the Construction Funds and inspecting the restoration and repair work,
     including without limitation attorneys' and other professional fees and
     escrow fees and expenses.

     14.7 NET PROCEEDS PAID TO FACILITY MORTGAGEE. Notwithstanding anything
herein to the contrary, if any Facility Mortgagee is entitled to any Net
Proceeds, or any portion thereof, under the terms of any Facility Mortgage, the
Net Proceeds shall be applied, held and/or disbursed in accordance with the
terms of the Facility Mortgage. Lessor shall make commercially reasonable
efforts to cause the Net Proceeds to be applied to the restoration of the Leased
Properties.

     14.8 TERMINATION OF LEASE. Notwithstanding anything herein to the contrary,
in the event the amount of the Net Proceeds from any one (1) occurrence, (i)
exceeds $80,000,000.00, or (ii) exceeds $20,000,000.00 during the final two (2)
years of the Realty Term, Lessor may exercise its option to require Lessee to
purchase the Leased Properties as set forth in Section 42.2.

                                   ARTICLE XV

                                  CONDEMNATION

     15.1 TOTAL TAKING OR OTHER TAKING WITH EITHER LEASED PROPERTY RENDERED
UNSUITABLE FOR ITS PRIMARY INTENDED USE. If title to the fee of the whole of a
Leased Property is Taken, this Lease shall cease and terminate as to the Leased
Property Taken as of the Date of Taking by the Condemnor and Rent shall be
apportioned as of the termination date, provided, however, that if the Award to
Lessor is less than the Repurchase Price for such Leased Property at the time of
such Award, it shall be a condition precedent to the termination of this Lease
as to such Leased Property that Lessee pay the amount of the deficiency to
Lessor. If title to the fee of less than the whole of a Leased Property is
Taken, but such Leased Property is thereby rendered Unsuitable for Its Primary
Intended Use, Lessee and Lessor shall each have the option by written Notice to
the other, at any time prior to the taking of possession by, or the date of
vesting of title in, the Condemnor, whichever first occurs, to terminate this
Lease with respect to such Leased Property as of the date so determined, in
which event this Lease shall thereupon so cease and terminate as of the earlier
of the date specified in such Notice or the date on which possession is taken by
the Condemnor. If this Lease is so terminated as to a Leased Property, Rent
shall be apportioned as of the termination date, and Lessee shall be deemed to
have elected to purchase such Leased Property for the Repurchase Price therefor.
Lessee shall complete the purchase within forty-five (45) days of the Taking,
and Lessee shall receive credit against such Repurchase Price for any portion of
the Award received by Lessor.

     15.2 ALLOCATION OF AWARD. The total Award made with respect to all or any
portion of a Leased Property or for loss of Rent, or for loss of business, shall
be solely the property of and payable to Lessor. Nothing contained in this Lease
will be deemed to create any additional interest in Lessee, or entitle Lessee to
any payment based on the value of the unexpired

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<PAGE>

term or so-called "bonus value" to Lessee of this Lease. Any Award made for the
taking of Lessee's Personal Property that is not integral to the Primary
Intended Use of the Facilities, or for removal and relocation expenses of Lessee
in any such Proceeding shall be payable to Lessee. Any Award made for the taking
of Lessee's Personal Property that is integral to the Primary Intended Use of
the Facilities shall be payable to Lessor. In any Proceeding with respect to an
Award, Lessor and Lessee shall each seek its own Award in conformity herewith,
at its own expense. Notwithstanding the foregoing, Lessee may pursue a claim for
loss of its business, provided that under the laws of the State, such claim will
not diminish the Award to Lessor.

     15.3 PARTIAL TAKING. In the event of a Partial Taking, and Lessee, at its
own cost and expense, shall within sixty (60) days of the taking of possession
by, or the date of vesting of title in, the Condemnor, whichever first
occurs/date on which such Notice is given commence the restoration of the Leased
Premises to a complete architectural unit of the same general character and
condition (as nearly as may be possible under the circumstances) as existed
immediately prior to the Partial Taking, and complete such restoration with all
reasonable dispatch, but in any event within one hundred eighty (180) days of
the date on which such Notice is given. Lessor shall contribute to the cost of
restoration only such portion of the Award as is made therefor. As long as no
Event of Default has occurred and is continuing, if such portion of the Award is
in an amount less than the Approval Threshold, Lessor shall pay the same to
Lessee upon completion of such restoration. As long as no Event of Default has
occurred and is continuing, if such portion of the Award is in an amount equal
to or greater than the Approval Threshold, Lessor shall make such portion of the
Award available to Lessee in the manner provided in Section 14.6 with respect to
Net Proceeds in excess of the Approval Threshold.

     15.4 TEMPORARY TAKING. If there is a Taking of possession or the use of all
or part of a Leased Property, but the fee of such Leased Property is not Taken
in whole or in part, until such Taking of possession or use continues for more
than six (6) months, all the provisions of this Lease shall remain in full force
and effect and the entire amount of any Award made for such Taking shall be paid
to Lessee provided there is then no Event of Default. Upon the termination of
any such period of temporary use or occupancy, Lessee at its sole cost and
expense shall restore the affected Leased Property, as nearly as may be
reasonably possible, to the condition existing immediately prior to such Taking.
If any temporary Taking continues for longer than six (6) months, and fifty
percent (50%) or more of any Leased Property is thereby rendered Unsuitable for
Its Primary Use, this Lease shall cease and terminate as to the affected Leased
Property as of the last day of the sixth (6th) month, but if less than fifty
percent (50%) of such Facility is thereby rendered Unsuitable for Its Primary
Use, Lessee and Lessor shall each have the option by at least sixty (60) day's
prior written Notice to the other, at any time prior to the end of the temporary
taking, to terminate this Lease as to the affected Leased Property of the date
set forth in such Notice, and Lessor shall be entitled to any Award made for the
period of such temporary Taking prior to the date of termination of the Lease.
In no event shall Rent or any Additional Charges abate during the period of any
temporary Taking.

     15.5 AWARDS PAID TO FACILITY MORTGAGEE. Notwithstanding anything herein to
the contrary, if any Facility Mortgagee is entitled to any Award or any portion
thereof, under the terms of any Facility Mortgage such Award shall be applied,
held and/or disbursed in

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<PAGE>

accordance with the terms of the Facility Mortgage. If the Facility Mortgagee
elects to apply the Award to the indebtedness secured by the Facility Mortgage:
(i) if the Award represents an Award for Partial Taking as described in Section
15.3 above, Lessee shall restore the affected Facility (as nearly as possible
under the circumstances) to a complete architectural unit of the same general
character and condition as that of the Facility existing immediately prior to
such Taking; or (ii) if the Award represents an Award for a Total Taking as
described in Section 15.1 above, Lessee shall pay to Lessor an amount equal to
the Repurchase Price and Lessor shall transfer its portion of the award and its
interest in the affected Leased Property to Lessee. In any such restoration or
purchase, Lessee shall receive full credit for any portion of any award retained
by Lessor and the Facility Mortgagee.

                                   ARTICLE XVI

                       LESSOR'S RIGHTS ON EVENT OF DEFAULT

     16.1 LESSOR'S RIGHTS UPON AN EVENT OF DEFAULT. If an Event of Default shall
occur Lessor may terminate this Lease by giving Lessee a Notice of Termination,
and in such event, the Term shall end and all rights of Lessee under this Lease
shall cease on the Termination Date. The Notice of Termination shall be in lieu
of and not in addition to any notice required by the laws of any State as a
condition to bringing an action for possession of the Leased Premises or to
recover damages under this Lease. In addition to Lessor's right to terminate
this Lease, Lessor shall have all other rights set forth in this Lease and all
remedies available at law and in equity. Lessee shall, to the extent permitted
by law, pay as Additional Charges all costs and expenses incurred by or on
behalf of Lessor, including, without limitation, reasonable attorneys' fees and
expenses (whether or not litigation is commenced, and if litigation is
commenced, including fees and expenses incurred in any appeals and post judgment
Proceeding) as a result of any default of Lessee hereunder.

     16.2 CERTAIN REMEDIES. If an Event of Default shall occur, whether or not
this Lease has been terminated pursuant to Section 16.1, if required to do so by
Lessor, Lessee shall immediately surrender to Lessor the Leased Properties to
Lessor in the condition required by Section 9.1.5 and quit the same, and Lessor
may enter upon and repossess the Leased Properties by reasonable force, any
summary Proceeding, ejectment or otherwise, and may remove Lessee and all other
persons and any and all personal properties from the Leased Properties, subject
to any Legal Requirements. In addition to all other remedies set forth or
referred to in this Article XVI.

     16.3 DAMAGES. Neither (i) the termination of this Lease pursuant to Section
16.1, (ii) the repossession of the Leased Properties, (iii) the failure of
Lessor to relet the Leased Properties, (iv) the reletting of all or any portion
thereof, nor (v) the failure of Lessor to collect or receive any rentals due
upon such any reletting, shall relieve Lessee of its liability and obligations
hereunder, all of which shall survive any such termination, repossession or
reletting. In the event this Lease is terminated by Lessor, Lessee shall
forthwith pay to Lessor all accrued and future Rent due and payable with respect
to the Leased Properties to and including the Realty Expiration Date all of
which shall become immediately due and payable, including without limitation all
interest and late

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<PAGE>

charges payable under Section 3.3 with respect to any late payment of such Rent,
and all Additional Charges.

     16.4 LESSEE'S OBLIGATION TO PURCHASE. If an Event of Default occurs, Lessor
may require Lessee to purchase the Leased Properties on the first Rent payment
date occurring after the date of receipt of, or such later date as may be
specified in, a Notice from Lessor requiring such purchase. The purchase price
of the Leased Properties shall be an amount equal to the then Repurchase Price
of the Leased Properties, plus all Rent then due and payable (excluding the
installment of Base Rent due on the purchase date) as of the date of purchase.
If Lessor exercises such right, Lessor shall convey the Leased Properties to
Lessee on the date fixed therefor upon receipt of such purchase price and this
Lease shall thereupon terminate. Any purchase by Lessee of the Leased Properties
pursuant to this Section shall be credited against the damages specified in
Section 16.3.

     16.5 WAIVER. If this Lease is terminated pursuant to Section 16.1, Lessee
waives, to the extent permitted by applicable law, (i) any right of reentry,
repossession or redesignation, (ii) any right to a trial by jury in the event of
any summary Proceeding to enforce the remedies set forth in this Article XVI,
and (iii) the benefit of any laws now or hereafter in force exempting property
from liability for rent or for debt. Acceptance of Rent at any time does not
prejudice or remove any right of Lessor as to any right or remedy. No course of
conduct shall be held to bar Lessor from literal enforcement of the terms of
this Lease.

     16.6 APPLICATION OF FUNDS. Any payments received by Lessor under any of the
provisions of this Lease during the existence or continuance of any Event of
Default shall be applied to Lessee's obligations in the order which Lessor may
determine or as may be prescribed by law.

     16.7 BANKRUPTCY.

          16.7.1 No Transfer. Neither Lessee's interest in this Lease, nor any
     estate hereby created in Lessee's interest nor any interest herein or
     therein, shall pass to any trustee or receiver or assignee for the benefit
     of creditors or otherwise by operation of law, except as may specifically
     be provided pursuant to the Bankruptcy Code (11 U.S.C. Section 101 et.
     seq.), as the same may be amended from time to time.

          16.7.2 Rights and Obligations Under the Bankruptcy Code.

                 Payment of Rent. Upon filing of a petition by or against Lessee
                 under the Bankruptcy Code, Lessee, as debtor and as
                 debtor-in-possession, and any trustee who may be appointed with
                 respect to the assets of or estate in bankruptcy of Lessee,
                 agree to pay monthly in advance on the first day of each month,
                 as reasonable compensation for the use and occupancy of the
                 Leased Properties, an amount equal to all Rent due pursuant to
                 this Lease.

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<PAGE>

                 Other Conditions and Obligations. Included within and in
                 addition to any other conditions or obligations imposed upon
                 Lessee or its successor in the event of the assumption and/or
                 assignment of the Lease are the following: (i) the cure of any
                 monetary defaults and reimbursement of pecuniary loss within
                 not more than thirty (30) days of assumption and/or assignment;
                 (ii) the deposit of an additional amount equal to not less than
                 three (3) months' Base Rent, which amount is agreed to be a
                 necessary and appropriate deposit to secure the future
                 performance under the Lease of Lessee or its assignee; (iii)
                 the continued use of the Leased Properties for the Primary
                 Intended Use; and (iv) the prior written consent of any
                 Facility Mortgagee.

     16.8 LESSOR'S RIGHT TO CURE LESSEE'S DEFAULT. If Lessee fails to make any
payment or perform any act required to be made or performed under this Lease,
and fails to cure the same within any grace or cure period applicable thereto,
upon such Notice as may be expressly required herein (or, if Lessor reasonably
determines that the giving of such Notice would risk loss to the Leased
Properties or cause damage to Lessor, upon such Notice as is practical under the
circumstances), and without waiving or releasing any obligation of Lessee,
Lessor may make such payment or perform such act for the account and at the
expense of Lessee, and may, to the extent permitted by law, enter upon the
Leased Properties for such purpose and take all such action thereon as, in
Lessor's sole opinion, may be necessary or appropriate. No such entry shall be
deemed an eviction of Lessee. All amounts so paid by Lessor and all costs and
expenses (including, without limitation, reasonable attorneys' fees and
expenses) so incurred, together with the late charge and interest provided for
in Section 3.3 thereon, shall be paid by Lessee to Lessor on demand. The
obligations of Lessee and rights of Lessor contained in this Article shall
survive the expiration or earlier termination of this Lease.

                                  ARTICLE XVII

              ADDITIONAL REPRESENTATIONS, WARRANTIES AND COVENANTS

     17.1 ADDITIONAL REPRESENTATIONS, WARRANTIES AND COVENANTS. Lessee,
Guarantor, and WCG each jointly and severally represent, warrant and covenant
that:

          17.1.1 Organization; Powers. Both Lessee and Guarantor are duly
     organized, validly existing and in good standing under the laws of the
     jurisdiction of its organization, has all requisite power and authority to
     carry on its business as now conducted and, except where the failure to do
     so, individually or in the aggregate, could not reasonably be expected to
     result in a Material Adverse Effect, is qualified to do business in, and is
     in good standing in, every jurisdiction where such qualification is
     required.

          17.1.2 Authorization; Enforceability. The execution of and performance
     under this Lease is within each of the Lessee's and Guarantor' entity
     powers and has been duly authorized by all necessary member, corporate and,
     if required, stockholder action as the case may be. This Lease has been
     duly executed and delivered by each of the Lessee and Guarantor and
     constitutes a legal, valid and binding obligation of the Lessee and

                                       43
<PAGE>

     Guarantor (as the case may be), enforceable in accordance with its terms,
     subject to applicable bankruptcy, insolvency, reorganization, moratorium or
     other laws affecting creditors' rights generally and subject to general
     principles of equity, regardless of whether considered in a Proceeding in
     equity or at law.

          17.1.3 Governmental Approvals; No Conflicts. The Lease or any of the
     other documents contemplated herein, (a) does not require any consent or
     approval of, registration or filing with, or any other action by, any
     Governmental Authority, except such as have been obtained or made and are
     in full force and effect and except filings necessary to perfect Lessor's
     rights under this Lease, (b) will not violate any applicable law or
     regulation or the charter, by-laws or other organizational documents of
     Lessee or Guarantor or any order of any Governmental Authority, (c) will
     not violate or result in a default under any indenture, agreement or other
     instrument binding upon Lessee or Guarantor or any of their respective
     assets, or give rise to a right thereunder to require any payment to be
     made by Lessee or Guarantor, and (d) will not result in the creation or
     imposition of any Encumbrance on any asset of Lessee or Guarantor, except
     any Encumbrance created by or in accordance with the Lease.

          17.1.4 Financial Condition; No Material Adverse Change. Guarantor has
     heretofore furnished to Lessor consolidated balance sheet and statements of
     operations, stockholders equity and cash flows as of and for the fiscal
     years ended December 31, 1998, December 31, 1999 and December 31, 2000,
     audited by Ernst & Young LLP, independent public accountants. Such
     financial statements present fairly, in all material respects, the
     financial position and results of operations and cash flow of Guarantor as
     of such dates and for such periods in accordance with GAAP.

               17.1.4.1 Pro Formas. Guarantor has heretofore furnished to the
          Lessor its pro forma consolidated balance sheet as of December 31,
          2000 and projected pro forma statements of operations and cash flows
          for the fiscal year ended December 31, 2001. Such projected pro forma
          consolidated balance sheets and statements of operations and cash
          flows (i) have been prepared in good faith based on the same
          assumptions used to prepare the pro forma financial statements (which
          assumptions are believed by Lessee and Guarantor to be reasonable),
          (ii) are based on the best information available to Lessee and
          Guarantor after due inquiry, (iii) present fairly, in all material
          respects, the pro forma financial position of Lessee and Guarantor as
          of such date and for such periods.

               17.1.4.2 Material Contingent Liabilities. Except as disclosed in
          the financial statements referred to above, neither the Lessee or
          Guarantor has, as of the Effective Date, any material contingent
          liabilities, unusual material long-term commitments or unrealized
          material losses.

               17.1.4.3 Material Adverse Change. Since December 31, 2000, there
          has been no Material Adverse Change.

          17.1.5 Properties. Lessee and Guarantor each has good title to, or
     valid leasehold

                                       44
<PAGE>

     interests in, all its real and personal property material to its business
     (including the Leased Properties), except for minor defects in title that
     do not interfere with its ability to conduct its business as currently
     conducted or to utilize such properties for their intended purposes. None
     of the properties and assets of Lessee or Guarantor is subject to any
     Encumbrance other than Permitted Encumbrances, and Encumbrances created by
     or in connection with this Lease.

               17.1.5.1 Intellectual Property. Lessee and Guarantor each owns,
          or is licensed to use, all trademarks, trade names, copyrights,
          patents and other intellectual property material to its business, and
          the use thereof by Lessee and Guarantor does not infringe upon the
          rights of any other Person, except for any such infringements that,
          individually or in the aggregate, could not reasonably be expected to
          result in a Material Adverse Effect.

          17.1.6 Litigation and Environmental Matters. There is no action, suit
     or Proceeding by or before any arbitrator or Governmental Authority pending
     against or, to the knowledge of Lessee or Guarantor, threatened against or
     affecting Lessee or Guarantor (i) as to which there is a reasonable
     possibility of an adverse determination and that, if adversely determined,
     could reasonably be expected, individually or in the aggregate, to result
     in a Material Adverse Effect or (ii) that involve this Lease or any of the
     other documents contemplated herein.

               17.1.6.1 Environmental Compliance. Except with respect to other
          matters that, individually or in the aggregate, could not reasonably
          be expected to result in a Material Adverse Effect, neither Lessee nor
          Guarantor (i) has failed to comply with any Environmental Law or to
          obtain, maintain or comply with any permit, license or other approval
          required under any Environmental Law, (ii) has become subject to any
          liability with respect to any Environmental Law, (iii) has received
          written notice of any claim with respect to any Environmental Law or
          (iv) knows of any basis for any violations of any Environmental Law or
          any release, threatened release or exposure to any Hazardous Materials
          that is likely to form the basis of any liability under any
          Environmental Law.

          17.1.7 Compliance with Laws and Agreements. Lessee and Guarantor each
     is in compliance with all laws, regulations and orders of any Governmental
     Authority applicable to it or its property and all indentures, agreements
     and other instruments binding upon it or its property, except where the
     failure to do so, individually or in the aggregate, could not reasonably be
     expected to result in a Material Adverse Effect. No Default has occurred
     and is continuing.

          17.1.8 Investment and Holding Company Status. Neither Lessee or
     Guarantor is (a) an "investment company" as defined in, or subject to
     regulation under, the Investment Company Act of 1940 or (b) a "holding
     company" as defined in, or subject to regulation under, the Public Utility
     Holding Company Act of 1935.

          17.1.9 Taxes. Lessee, Guarantor, and WCG each has timely filed or
     caused to be

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<PAGE>

     filed all tax returns and reports required to have been filed and has paid
     or caused to be paid all taxes required to have been paid by or with
     respect to it, except (a) taxes that are being contested in good faith by
     an appropriate Proceeding and for which Lessee or Guarantor, as applicable,
     has set aside on its books adequate reserves or (b) to the extent that the
     failure to do so could not reasonably be expected to result in a Material
     Adverse Effect.

          17.1.10 ERISA. No ERISA Event has occurred or is reasonably expected
     to occur that, when taken together with all other such ERISA Events for
     which liability is reasonably expected to occur, could reasonably be
     expected to result in a Material Adverse Effect. The present value of all
     accumulated benefit obligations under each Plan (based on the assumptions
     used for purposes of Statement of Financial Accounting Standards No. 87)
     did not, as of the date of the most recent financial statements reflecting
     such amounts, exceed by more than $25,000,000 the fair market value of the
     assets of such Plan, and the present value of all accumulated benefit
     obligations of all underfunded Plans (based on the assumptions used for
     purposes of Statement of Financial Accounting Standards No. 87) did not, as
     of the date of the most recent financial statements reflecting such
     amounts, exceed by more than $25,000,000 the fair market value of the
     assets of all such underfunded Plans.

          17.1.11 Disclosure. Lessee and Guarantor have disclosed to the Lessor
     all agreements, instruments and corporate or other restrictions to which
     Lessee or Guarantor is subject, and all other matters known to any of them,
     that, individually or in the aggregate, could reasonably be expected to
     result in a Material Adverse Effect. None of the reports, financial
     statements, certificates or other information furnished by or on behalf of
     Lessee or Guarantor in connection with the negotiation of this Lease or
     delivered hereunder (as modified or supplemented by other information so
     furnished) contains any material misstatement of fact or omits to state any
     material fact necessary to make the statements therein, in the light of the
     circumstances under which they were made, not misleading; provided that,
     with respect to projected financial information, Lessee and Guarantor
     represent only that such information was prepared in good faith based upon
     assumptions believed to be reasonable at the time.

          17.1.12 Insurance. As of the Effective Date, all premiums in respect
     of all insurance described in Article XIII have been paid.

          17.1.13 Labor Matters. As of the Effective Date, there are no
     strikes, lockouts or slowdowns against Lessee or Guarantor pending or, to
     the knowledge of Lessee or Guarantor, threatened. The hours worked by and
     payments made to employees of Lessee and Guarantor have not been in
     violation of the Fair Labor Standards Act or any other applicable Federal,
     state, local or foreign law dealing with such matters. All payments due
     from Lessee or Guarantor, or for which any claim may be made against Lessee
     or Guarantor, on account of wages and employee health and welfare insurance
     and other benefits, have been paid or accrued as a liability on the books
     of Lessee or Guarantor. The execution of this Lease has not and will not
     give rise to any right of termination or right of renegotiation on the part
     of any union under any collective bargaining agreement by which Lessee or
     Guarantor is bound.

                                       46
<PAGE>

          17.1.14 Solvency. Immediately after the Effective Date and
     immediately following the purchase of the Leased Properties by Lessor
     pursuant to the Purchase Agreement made on the Effective Date and after
     giving effect to the application of the Purchase Price, (a) the fair value
     of the assets of Lessee, Guarantor, and WCG will exceed its debts and
     liabilities, subordinated, contingent or otherwise; (b) the present fair
     saleable value of the property of Lessee, Guarantor and WCG will be greater
     than the amount that will be required to pay the probable liability of its
     debts and other liabilities, subordinated, contingent or otherwise, as such
     debts and other liabilities become absolute and matured; (c) Lessee,
     Guarantor, and WCG each will be able to pay its debts and liabilities,
     subordinated, contingent or otherwise, as such debts and liabilities become
     absolute and matured; and (d) Lessee, Guarantor, and WCG each will not have
     unreasonably small capital with which to conduct the business in which it
     is engaged as such business is now conducted and is proposed to be
     conducted following the Effective Date.

          17.1.15 No Burdensome Restrictions. No contract, lease, agreement or
     other instrument to which Lessee or Guarantor is a party or by which any of
     its property is bound or affected, no charge, corporate restriction,
     judgment, decree or order and no provision of applicable law or
     governmental regulation could reasonably be expected to have Material
     Adverse Effect.

          17.1.16 Representations True and Correct. As of the dates when made
     and as of the Effective Date, each representation and warranty of Lessee or
     Guarantor thereto contained in the Purchase Agreement, this Lease or any
     other documents executed in connection herewith, is true and correct.

                                  ARTICLE XVIII

                       OCCUPANCY AFTER EXPIRATION OF TERM

     18.1 HOLDING OVER. If Lessee remains in possession of all or any of the
Leased Properties after the expiration of the Term or earlier termination of
this Lease, such possession shall be as a month-to-month tenant, and throughout
the period of such possession Lessee shall pay as Rent for each month one
hundred fifty percent (150%) times the sum of: (i) one-twelfth (1/12th) of the
Base Rent payable during the Lease Year in which such expiration or termination
occurs, plus (ii) all Additional Charges accruing during the month, plus (iii)
any and all other sums payable by Lessee pursuant to this Lease. During such
period of month-to-month tenancy, Lessee shall be obligated to perform and
observe all of the terms, covenants and conditions of this Lease, but shall have
no rights hereunder other than the right, to the extent given by applicable law
to month-to-month tenancies, to continue its occupancy and use of the Leased
Properties until the month-to-month tenancy is terminated. Nothing contained
herein shall constitute the consent, express or implied, of Lessor to the
holding over of Lessee after the expiration or earlier termination of this
Lease.

                                       47
<PAGE>

     18.2 INDEMNITY. If Lessee fails to surrender the Leased Properties in a
timely manner and in accordance with the provisions of Section 9.1.5 upon the
expiration or termination of this Lease, in addition to any other liabilities to
Lessor accruing therefrom, Lessee shall defend, indemnify and hold Lessor, its
principals, officers, directors, agents and employees harmless from loss or
liability resulting from such failure, including, without limiting the
generality of the foregoing, loss of rental with respect to any new lease in
which the rental payable thereunder exceeds the Rent paid by Lessee pursuant to
this Lease during Lessee's hold-over and any claims by any proposed new tenant
founded on such failure. The provisions of this Section 18.2 shall survive the
expiration or termination of this Lease.

                                   ARTICLE XIX

                          SUBORDINATION AND ATTORNMENT

     19.1 SUBORDINATION. Upon written request of Lessor, any Facility Mortgagee,
or the beneficiary of any deed of trust of Lessor, Lessee will enter into a
written agreement subordinating its rights pursuant to this Lease (i) to the
lien of any mortgage, deed of trust or the interest of any lease in which Lessor
is the lessee and to all modifications, extensions, substitutions thereof (or,
at Lessor's option, agree to the subordination to this Lease of the lien of said
mortgage, deed of trust or the interest of any lease in which Lessor is the
lessee), and (ii) to all advances made or hereafter to be made thereunder. In
connection with any such request, Lessor shall provide Lessee with a
"Non-Disturbance Agreement" reasonably acceptable to such mortgagee, beneficiary
or lessor providing that if such mortgagee, beneficiary or lessor acquires the
Leased Properties by way of foreclosure or deed in lieu of foreclosure, such
mortgagee, beneficiary or lessor will not disturb Lessee's possession under this
Lease and will recognize Lessee's rights hereunder if and for so long as no
Event of Default has occurred and is continuing. Lessee agrees to consent to
amend this Lease as reasonably required by the Facility Mortgagee, and shall be
deemed to have unreasonably withheld or delayed its consent if the required
changes do not materially (i) alter the economic terms of this Lease, (ii)
diminish the rights of Lessee, or (iii) increase the obligations of Lessee,
provided that Lessee shall also have received the non-disturbance agreement
provided for in this Article.

     19.2 ATTORNMENT. If any Proceeding is brought for foreclosure, or if the
power of sale is exercised under any mortgage or deed of trust made by Lessor
encumbering the Leased Properties, or if a lease in which Lessor is the lessee
is terminated, Lessee shall attorn to the purchaser or lessor under such lease
upon any foreclosure or deed in lieu thereof, sale or lease termination and
recognize the purchaser or lessor as Lessor under this Lease, provided the
purchaser or lessor acquires and accepts the Leased Properties subject to this
Lease.

     19.3 LESSEE'S CERTIFICATE. Lessee shall, upon not less than ten (10) days
prior Notice from Lessor, execute, acknowledge and deliver to Lessor, Lessee's
Certificate containing then-current facts. It is intended that any Lessee's
Certificate delivered pursuant hereto may be relied upon by Lessor, any
prospective tenant or purchaser of the Leased Properties, any mortgagee or
prospective mortgagee, and by any other party who may reasonably rely on such
statement. Lessee's failure to deliver the Lessee's Certificate within such time
shall constitute an

                                       48
<PAGE>

Event of Default. In addition, Lessee hereby authorizes Lessor to execute and
deliver a certificate to the effect (if true) that Lessee represents and
warrants that (i) this Lease is in full force and effect without modification,
and (ii) Lessor is not in breach or default of any of its obligations under this
Lease.

                                   ARTICLE XX

                                  RISK OF LOSS

     20.1 RISK OF LOSS. During the Term, the risk of loss or of decrease in the
enjoyment and beneficial use of the Leased Properties in consequence of the
damage or destruction thereof by fire, the elements, casualties, thefts, riots,
wars or otherwise, or in consequence of foreclosures, attachments, levies or
executions is assumed by Lessee, and, in the absence of gross negligence,
willful misconduct or material breach of this Lease by Lessor, Lessor shall in
no event be answerable or accountable therefor nor shall any of the events
mentioned in this Article XX entitle Lessee to any abatement of Rent.

                                   ARTICLE XXI

                                 INDEMNIFICATION

     21.1 INDEMNIFICATION. Notwithstanding the existence of any insurance or
self-insurance provided for in Article XIII, and without regard to the policy
limits of any such insurance or self-insurance, Lessee shall protect, indemnify,
save harmless and defend Lessor, its principals, officers, directors, agents,
employees, parents, and affiliates from and against all liabilities,
obligations, claims, damages, penalties, causes of action, costs and expenses
(including, without limitation, reasonable attorneys' fees and expenses), to the
extent permitted by law, imposed upon or incurred by or asserted against Lessor
by reason of: (i) any accident, injury to or death of persons or loss of or
damage to property occurring on or about the Leased Properties or adjoining
sidewalks, including without limitation any claims of malpractice, (ii) any use,
misuse, non-use, condition, maintenance or repair by Lessee of the Leased
Properties, (iii) the failure to pay any Impositions, (iv) any failure on the
part of Lessee to perform or comply with any of the terms of this Lease, and (v)
the nonperformance of any contractual obligation, express or implied, assumed or
undertaken by Lessee or any party in privity with Lessee with respect to the
Leased Properties or any business or other activity carried on with respect to
the Leased Properties during the Term or thereafter during any time in which
Lessee or any such other party is in possession of the Leased Properties or
thereafter to the extent that any conduct by Lessee or any such person (or
failure of such conduct thereby if the same should have been undertaken during
such time of possession and leads to such damage or loss) causes such loss or
claim. Any amounts which become payable by Lessee under this Section shall be
paid within ten (10) days after liability therefor on the part of Lessee is
determined by litigation or otherwise, and if not timely paid, shall bear
interest (to the extent permitted by law) at the Overdue Rate from the date of
such determination to the date of payment. Nothing herein shall be construed as
indemnifying Lessor against its own grossly negligent acts or omissions or
willful misconduct. Lessee's liability under this Article shall survive the
expiration or any earlier termination of this Lease.

                                       49
<PAGE>

                                  ARTICLE XXII

                            RESTRICTIONS ON TRANSFERS

     22.1 GENERAL PROHIBITION AGAINST TRANSFERS. Lessee acknowledges that a
significant inducement to Lessor to enter into this Lease with Lessee on the
terms set forth herein is the combination of financial strength, experience,
skill and reputation possessed by the Lessee named herein, the Person or Persons
in Control of Lessee and Guarantor, together with Lessee's assurance that Lessor
shall have the unrestricted right to approve or disapprove any proposed
Transfer. Therefore, there shall be no Transfer except as specifically permitted
by this Lease or consented to in advance by Lessor in writing. Lessee agrees
that Lessor shall have the right to withhold its consent to any proposed
Transfer on the basis of Lessor's judgment as to the effect the proposed
Transfer may have on the Leased Properties and the future performance of the
obligations of the Lessee under this Lease, whether or not Lessee agrees with
such judgment. Any attempted Transfer which is not specifically permitted by
this Lease or consented to by Lessor in advance in writing shall be null and
void and of no force and effect whatsoever. In the event of a Transfer, Lessor
may collect Rent and other charges from the assignee, subtenant or other
occupant or transferee (any and all of which are herein referred to as a
"Transferee") and apply the amounts collected to the Rent and other charges
herein reserved, but no Transfer or collection of Rent and other charges shall
be deemed to be a waiver of Lessor's rights to enforce Lessee's covenants or an
acceptance of the Transferee as Lessee, or a release of the Lessee named herein
from the performance of its covenants. Notwithstanding any Transfer, Lessee and
Guarantor shall remain fully liable for the performance of all terms, covenants
and provisions of this Lease. Any violation of this Lease by any Transferee
shall be deemed to be a violation of this Lease by Lessee.

     22.2 CONSENT TO CERTAIN TRANSFERS. Lessor acknowledges that Lessee, as
sublessor, intends to enter into subleases with the parties identified on
SCHEDULE 22.2, as sublessees, with respect to the Facilities identified on such
Schedule. Lessor consents to such subleases provided that all such sublease
agreements satisfy all of the requirements set forth in this Lease and otherwise
are satisfactory in form and substance to Lessor. The conditions set forth in
the immediately preceding sentence shall be deemed satisfied as to any sublease
with respect to which Lessor has executed and delivered a Consent and
Non-Disturbance Agreement in substantially the form of EXHIBIT F.
Notwithstanding any such sublease, Lessee and Guarantor shall remain fully
liable for the performance of all terms, covenants and provisions of this Lease.

     22.3 SUBORDINATION AND ATTORNMENT. Lessee shall insert in any sublease
permitted by Lessor provisions to the effect that (i) such sublease is subject
and subordinate to all of the terms and provisions of this Lease and to the
rights of Lessor hereunder, (ii) if this Lease terminates before the expiration
of such sublease, the sublessee thereunder will, at Lessor's option, attorn to
Lessor and waive any right the sublessee may have to terminate the sublease or
to surrender possession thereunder, as a result of the termination of this
Lease, and (iii) if the sublessee receives a written Notice from Lessor or
Lessor's assignee, if any, stating that Lessee is in default under this Lease,
the sublessee shall thereafter be obligated to pay all rentals accruing

                                       50
<PAGE>

under the sublease directly to the party giving such Notice, or as such party
may direct, which payments shall be credited against the amounts owing by Lessee
under this Lease.

                                  ARTICLE XXIII

                        LESSEE AND GUARANTOR INFORMATION

     23.1 OFFICER'S CERTIFICATES AND FINANCIAL STATEMENTS. Lessee and Guarantor
shall furnish or cause to be furnished to Lessor:

          23.1.1 Fiscal Year Information. (i) within ninety (90) days after the
     end of each fiscal year of WCG, its audited consolidated balance sheets and
     related audited consolidated statements of operations, stockholders' or
     members' equity and cash flows as of the end of and for such fiscal year
     (including segment reporting with respect to each of WCG's business
     segments consistent), setting forth in each case in comparative form the
     figures for the previous fiscal year, all reported on by Ernst & Young LLP
     or other independent public accountants of recognized national standing,
     and otherwise reasonably satisfactory to Lessor (without a "going concern"
     or like qualification or exception and without any qualification or
     exception as to the scope of such audit) to the effect that such
     consolidated financial statements present fairly in all material respects
     the financial condition and results of operations of WCG on a consolidated
     basis in accordance with GAAP consistently applied, and (ii) within ninety
     (90) days after the end of each fiscal year of WCG, supplemental unaudited
     balance sheets and related unaudited statements of operations,
     stockholders' or members' equity and cash flows as of the end of and for
     such fiscal year, setting forth in tabular form in each case the figures
     for the previous year, for WCG and the consolidating adjustments with
     respect thereto.

          23.1.2 Quarterly Information. (i) within forty-five (45) days after
     the end of each of the first three (3) fiscal quarters of each fiscal year
     of WCG, unaudited consolidated and consolidating balance sheets and related
     consolidated and consolidating statements of operations, stockholders' or
     members' equity and cash flows of Guarantor and WCG as of the end of and
     for such fiscal quarter and the then elapsed portion of the fiscal year,
     setting forth in each case in comparative form the figures for the
     corresponding period or periods of the previous fiscal year (or in the case
     of the balance sheet, as of the end of the previous fiscal year), all
     certified by an Officer's Certificate as presenting fairly in all material
     respects the financial condition and results of operations of Guarantor and
     WCG on a consolidated basis in accordance with GAAP consistently applied,
     subject to normal year-end audit adjustments and the absence of footnotes
     and (ii) within forty-five (45) days after the end of each of the first
     three (3) fiscal quarters of each fiscal year of Guarantor, unaudited
     balance sheets and related statements of operations, stockholders' or
     members' equity and cash flow of Guarantor as of the end of and for such
     fiscal quarter and the then elapsed portion of the fiscal year, setting
     forth in each case in comparative form the figures for the corresponding
     period or periods of the previous fiscal year (or, in the case of the
     balance sheet, as of the end of the previous fiscal year) all certified by
     an Officer's Certificate as presenting fairly in all material respects the
     financial condition and results of

                                       51
<PAGE>

     operations of Guarantor in accordance with GAAP consistently applied,
     subject to normal year-end audit adjustments and the absence of footnotes.

          23.1.3 Officers Certificate. Concurrently with any delivery of
     financial statements under Sections 23.1.1 and 23.1.2, and at any time and
     from time to time, within ten (10) days of Lessor's request, an Officer's
     Certificate of the Lessee (i) certifying as to whether an Event of Default
     has occurred and, if an Event of Default has occurred, specifying the
     details thereof and any action taken or proposed to be taken with respect
     thereto, (ii) setting forth in reasonable detail calculations demonstrating
     compliance with Sections 8.4.2 through 8.4.6 (iii) stating whether any
     change in GAAP or in the application thereof has occurred since the date of
     audited financial statements referred to in Section 17.1.4 and, if any such
     change has occurred, specifying the effect of such change on the financial
     statements accompanying such Officer's Certificate, and (iv) certifying as
     to the compliance by Lessee and Guarantor, with the provisions of this
     Lease, and such other matters set forth in this Lease or the Credit
     Agreement, as Lessor may specify.

          23.1.4 Accounting Firm Certificate. Concurrently with any delivery of
     financial statements under Section 23.1.1, a certificate of the accounting
     firm that reported on such financial statements stating whether they
     obtained knowledge during the course of their examination of such financial
     statements of any Event of Default (which certificate may be limited to the
     extent required by accounting rules or guidelines).

          23.1.5 Budget. As soon as practicable after approval by the Board of
     Directors of WCG, and in any event not later than one hundred and twenty
     (120) days after the commencement of each fiscal year of WCG, a
     consolidated and consolidating budget of WCG for such fiscal year and a
     consolidated budget of the Lessee for such fiscal year and, promptly when
     available, any significant revisions of any such budget.

          23.1.6 SEC Filings. Promptly after the same become publicly available,
     copies of all periodic and other reports, proxy statements and other
     materials filed by WCG or any of its Affiliates with the SEC, or any
     Governmental Authority succeeding to any or all of the functions of the
     SEC, or with any national securities exchange, or distributed by WCG to its
     shareholders generally, as the case may be, except to the extent any such
     report, proxy statement or other material is available electronically on a
     publicly-accessible website.

          23.1.7 Other Information. Promptly following any request therefor,
     such other information regarding the operations, business affairs and
     financial condition of Lessee, Guarantor or WCG, or compliance with the
     terms of this Lease or any of the documents contemplated herein, as Lessor
     may reasonably request.

          23.1.8 Credit Agreement Information. To the extent not previously
     covered by the provisions of this Section 23.1, copies of all information
     provided by Guarantor, WCG or any Affiliates of either pursuant to the
     Credit Agreement, contemporaneously with its delivery pursuant thereto.

                                       52
<PAGE>

     23.2 PUBLIC OFFERING INFORMATION. Lessee, Guarantor and WCG, specifically
agree that subject to the approval of Lessee, which approval shall not be
unreasonably withheld or delayed, Lessor may include financial information and
information concerning the operation of the Facilities in offering memoranda or
prospectus, or similar publications in connection with syndications or public
offerings of Lessor's securities or interests, and any other reporting
requirements under applicable Federal and State Laws, including those of any
successor to Lessor. Lessee, Guarantor, and WCG, agree to provide such other
reasonable information necessary with respect to Lessee, Guarantor, and WCG, and
the Leased Properties to facilitate a public offering or to satisfy SEC or
regulatory disclosure requirements. Upon request of Lessor, Lessee shall notify
Lessor of any necessary corrections to information Lessor proposes to publish
within a reasonable period of time (not to exceed ten (10) days) after being
informed thereof by Lessor.

     23.3 NOTICES OF MATERIAL EVENTS. Upon its respective knowledge thereof,
Lessee and Guarantor each will furnish to Lessor prompt written notice of the
following. Each notice delivered under this Section shall be accompanied by a
statement of an Officer's Certificate, duly executed, setting forth the details
of the event or development requiring such notice and any action taken or
proposed to be taken with respect thereto.

          23.3.1 Event of Default. The occurrence of any Event of Default.

          23.3.2 Action, Suit or Proceeding. The filing or commencement of any
     action, suit or Proceeding by or before any arbitrator or Governmental
     Authority against or affecting Lessee, Guarantor or WCG or any Affiliate
     thereof that could reasonably be expected to result in a Material Adverse
     Effect.

          23.3.3 ERISA Event. The occurrence of any ERISA Event that, alone or
     together with any other ERISA Events that have occurred, could reasonably
     be expected to result in a Material Adverse Effect.

          23.3.4 Other Matters. Any other development that results in, or could
     reasonably be expected to result in, a Material Adverse Effect.

                                  ARTICLE XXIV

                                   INSPECTION

     24.1 LESSOR'S RIGHT TO INSPECT. Lessee shall permit Lessor and its
authorized representatives to inspect the Leased Properties and Lessee's books
and records pertaining thereto during normal business hours at any time upon
reasonable Notice. Notwithstanding the foregoing, Lessee is and shall be in
exclusive control and possession of the Leased Properties as provided herein,
and Lessor shall not in any event whatsoever be liable for any injury or damage
to any property or to any person happening on or about the Leased Properties nor
for any injury or damage to any property of Lessee, or of any other person,
except in the event any such injury

                                       53
<PAGE>

or damage is the direct result of the gross negligence or malfeasance of Lessor.
The right of Lessor to enter and inspect the Leased Properties are for the
purpose of enabling Lessor to be informed as to whether or not Lessee is
complying with the terms, covenants and conditions of this Lease and to do such
acts as Lessee may have failed to do, provided however, in no event shall Lessor
have any obligation whatsoever to so perform such acts.

                                   ARTICLE XXV

                                    NO WAIVER

     25.1 NO WAIVER. No failure by Lessor to insist upon the strict performance
of any term hereof or to exercise any right, power or remedy consequent upon a
breach hereof, and no acceptance of full or partial payment of Rent during the
continuance of any such breach, shall constitute a waiver of any such breach or
of any such term. No waiver of any breach shall affect or alter this Lease,
which shall continue in full force and effect with respect to any other then
existing or subsequent breach.

                                  ARTICLE XXVI

                               REMEDIES CUMULATIVE

     26.1 REMEDIES CUMULATIVE. To the extent permitted by law, each legal,
equitable or contractual right, power and remedy of Lessor now or hereafter
provided either in this Lease or by statute or otherwise shall be cumulative and
concurrent and shall be in addition to every other right, power and remedy and
the exercise or beginning of the exercise by Lessor of any one or more of such
rights, powers and remedies shall not preclude the simultaneous or subsequent
exercise by Lessor of any or all of such other rights, powers and remedies.

                                  ARTICLE XXVII

                                    SURRENDER

     27.1 ACCEPTANCE OF SURRENDER. No surrender to Lessor of this Lease or of
the Leased Properties or any part thereof, or of any interest therein, shall be
valid or effective unless agreed to and accepted in writing by Lessor, and no
act by Lessor or any representative or agent of Lessor, other than such a
written acceptance by Lessor, shall constitute an acceptance of any such
surrender.

                                  ARTICLE XXIII

                                  RELATIONSHIP

     28.1 NO MERGER OF TITLE. There shall be no merger of this Lease or of the
leasehold estate created hereby by reason of the fact that the same person,
firm, corporation or other entity may acquire, own or hold, directly or
indirectly, (i) this Lease or the leasehold estate

                                       54
<PAGE>

created hereby or any interest in this Lease or such leasehold estate, and (ii)
the fee estate in the Leased Properties.

     28.2 NO PARTNERSHIP. Nothing contained in this Lease will be deemed or
construed to create a partnership or joint venture between Lessor and Lessee or
to cause either party to be responsible in any way for the debts or obligations
of the other or any other party, it being the intention of the parties that the
only relationship hereunder is that of Lessor and Lessee.

                                  ARTICLE XXIX

                              CONVEYANCE BY LESSOR

     29.1 CONVEYANCE BY LESSOR. Lessor may at its sole option, transfer the
Leased Properties and in connection with any such transfer, may assign this
Lease. If Lessor or any successor owner of the Leased Properties conveys the
Leased Properties other than as security for a debt, Lessor or such successor
owner, as the case may be, shall thereupon be released from all future
liabilities and obligations of Lessor under this Lease arising or accruing from
and after the date of such conveyance or other transfer and all such future
liabilities and obligations shall thereupon be binding upon the new owner.

                                   ARTICLE XXX

                                 QUIET ENJOYMENT

     30.1 QUIET ENJOYMENT. So long as Lessee pays all Rent as it becomes due and
complies with all of the terms of this Lease and performs its obligations
hereunder, Lessee shall peaceably and quietly have, hold and enjoy the Leased
Properties for the Term, free of any claim or other action by Lessor or anyone
claiming by, through or under Lessor, but subject to all liens and Encumbrances
of record as of the date hereof or hereafter provided for in this Lease or
consented to by Lessee. Except as otherwise provided in this Lease, no failure
by Lessor to comply with the foregoing covenant will give Lessee any right to
cancel or terminate this Lease or abate, reduce or make a deduction from or
offset against the Rent or any other sum payable under this Lease, or to fail to
perform any other obligation of Lessee. Lessee shall, however, have the right,
by separate and independent action, to pursue any claim it may have against
Lessor as a result of a breach by Lessor of the covenant of quiet enjoyment
contained in this Section.

                                       55
<PAGE>

                                  ARTICLE XXXI

                                     NOTICES

     31.1 NOTICES. Any notice, request or other communication to be given by any
party hereunder shall be in writing and shall be sent by registered or certified
mail, postage prepaid, by overnight deliver, hand delivery or facsimile
transmission to the following address:

     To Lessor:      Williams Headquarters Building Company
                     Attn: George D. Shahadi, Vice President-Corp.
                           Real Estate
                     One Williams Center, Suite 2200
                     Tulsa, Oklahoma 74172
                     Fax No. 918/573-4049

     With copies to: The Williams Companies, Inc.
                     Attn: Real Estate Counsel
                     One Williams Center, Suite 4100
                     Tulsa, Oklahoma 74172
                     Fax No. 918/ 573-4503

                     The Williams Companies, Inc.
                     Attn: Treasurer
                     One Williams Center, Suite 5000
                     Tulsa, Oklahoma 74172
                     Fax No. 918/ 573-2065

     To Lessee:      Williams Technology Center, LLC
                     Attn: Vice President, Real Estate
                     One Williams Center, MD-OneOK-6
                     Tulsa, Oklahoma 74172
                     Fax No. 918/ 573-5614

     With copy to:   Williams Communications, LLC.
                     Attn: P. David Newsome, Jr., Esq., General Counsel
                     One Williams Center, MD-41-3
                     Tulsa, Oklahoma 74172
                     Fax No. 918/ 573-3005

     To Guarantor:   Williams Communications, LLC
                     Attn: P. David Newsome, Jr., Esq., General Counsel
                     One Williams Center, MD-41-3
                     Tulsa, Oklahoma 74172
                     Fax No. 918/ 573-3005

     With copy to:   Williams Communications, LLC
                     Attn: Assistant Treasurer
                     One Technology Center, MD: TC 14X
                     Tulsa, Oklahoma 74103
                     Fax No.: 918/547-1108

                                       56
<PAGE>

or to such other address as either party may hereafter designate. Notice shall
be deemed to have been given on the date of delivery if such delivery is made on
a Business Day, or if not, on the first Business Day after delivery. If delivery
is refused, Notice shall be deemed to have been given on the date delivery was
first attempted. Notice sent by facsimile transmission shall be deemed given
upon confirmation that such Notice was received at the number specified above or
in a Notice to the sender. If Lessee has vacated the Leased Properties, Lessor's
Notice may be posted on the door of a Leased Property. No failure of any
addressee designated as "With copy to", to be sent or to receive any Notice
shall invalidate the effectiveness of Notice sent to and received by any party
to this Lease.

                                  ARTICLE XXXII

                             [INTENTIONALLY OMITTED]

                                 ARTICLE XXXIII

                             [INTENTIONALLY OMITTED]

                                  ARTICLE XXXIV

                           LESSOR'S OPTION TO PURCHASE

     34.1 LESSOR'S OPTION TO PURCHASE LESSEE'S PERSONAL PROPERTY. Unless Lessee
purchases the Leased Properties as provided in this Lease, upon the expiration
or termination of this Lease, Lessor shall have the option on the terms
hereinafter set forth to purchase any of Lessee's Personal Property that is not
deemed to have been sold, assigned, transferred and conveyed to Lessor pursuant
to Section 6.3 hereof, for an amount equal to the then book value thereof
(acquisition cost less accumulated depreciation on the books of Lessee
pertaining thereto), subject to, and with appropriate credits for, any
obligations owing from Lessee to Lessor and for the then outstanding balances
owing on all equipment leases, conditional sale contracts and any other
Encumbrances to which such Lessee's Personal Property is subject. Lessor's
option shall be exercised by Notice to Lessee no more than one hundred eighty
(180) days, nor less than ninety (90) days, before the expiration of the Realty
Term, unless this Lease is terminated prior to its expiration date by reason of
an Event of Default, in which event Lessor's option shall be exercised not more
than ninety (90) days after the date of termination. Lessor's option shall
terminate upon Lessee's purchase of the Leased Properties. If Lessee does not
receive Lessor's Notice exercising its option before the expiration of the
relevant time period, Lessee shall give Lessor Notice thereof and Lessor's
option shall continue in full force and effect for a period of thirty (30) days
after such Notice from Lessee. If Lessor exercises its option, Lessee shall, in

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exchange for Lessor's payment of the purchase price, deliver the purchased
Lessee's Personal Property to Lessor, together with a bill of sale and such
other documents as Lessor may reasonably request in order to carry out the
purchase, and the purchase shall be closed by such delivery and such payment on
the date set by Lessor in its Notice of exercise. Lessor shall be responsible
for applicable sales, use and other similar taxes which are assessed on the sale
of Lessee's Personal Property to Lessor.

     34.2 LEASED PROPERTIES TRADE NAME. If this Lease is terminated pursuant to
Section 16.1 or Lessor exercises its option to purchase Lessee's Personal
Property pursuant to Section 34.1, Lessee shall be deemed to have assigned to
Lessor the exclusive right to use Leased Properties Trade Name in perpetuity.

     34.3 TRANSFER OF OPERATIONAL CONTROL OF THE FACILITIES. Lessee shall
cooperate fully in transferring operational control of all of the Facilities
which are then subject to this Lease to Lessor or Lessor's nominee if the Term
expires without renewal or this Lease is terminated upon the occurrence of an
Event of Default or for any other reason, and Lessee shall use its best efforts
to cause the business conducted at all such Facilities to continue without
interruption. To that end, pending completion of the transfer of the operational
control of such Facilities to Lessor or its nominee:

          34.3.1 Employees. Lessee will not terminate the employment of any
     Leased Properties maintenance and operations employees without just cause,
     or change any salaries, provided, however, that without the advance written
     consent of Lessor, Lessee may grant pre-announced wage increases of which
     Lessor has knowledge, increases required by written employment agreements
     and normal raises to non-officers at regular review dates; and Lessee will
     not hire any additional employees except in good faith in the ordinary
     course of business;

          34.3.2 Change in Control. Lessee will provide all necessary
     information requested by Lessor or its nominee for the preparation and
     filing of any and all necessary applications or notifications of any
     federal or state governmental authority having jurisdiction over a change
     in the operational control of the Facilities, and any other information
     reasonably required to effect an orderly transfer of the Facilities;

          34.3.3 Business and Organization. Lessee shall use all reasonable
     efforts to keep the business and organization of the Facilities intact and
     to preserve for Lessor or its nominee the goodwill of the suppliers,
     distributors, residents and others having business relations with Lessee
     with respect to the Facilities;

          34.3.4 Operations in Ordinary Course. Lessee shall engage only in
     transactions or other activities with respect to the Facilities which are
     in the ordinary course of its business and shall perform all maintenance
     and repairs reasonably necessary to keep the Facilities in satisfactory
     operating condition and repair;

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<PAGE>

          34.3.5 Employee Benefits. Lessee shall provide Lessor or its nominee
     with full and complete information regarding the employees of the
     Facilities and shall reimburse Lessor or its nominee for all outstanding
     accrued employee benefits, including accrued vacation, sick and holiday pay
     calculated on a true accrual basis, including all earned and a prorated
     portion of all unearned benefits;

          34.3.6 Third Party Consents. Lessee shall use all reasonable efforts
     to obtain the acknowledgment and the consent of any creditor, lessor or
     sublessor, mortgagee, beneficiary of a deed of trust or security agreement
     affecting the real and personal properties of Lessee or any other party
     whose acknowledgment and/or consent would be required because of a change
     in the operational control of the Facilities and transfer of personal
     property. The consent must be in form, scope and substance satisfactory to
     Lessor or its nominee, including, without limitation, an acknowledgment in
     respect to all such contracts, leases, deeds of trust, mortgage, security
     agreements, or other agreements that Lessee and all predecessors or
     successors-in-interest thereto are not in default in respect thereto, that
     no condition known to the consenting party exists which with the giving of
     notice or lapse of time would result in such a default, and, if requested,
     affirmatively consenting to the change in the operational control of the
     Facilities;

          34.3.7 Lessor as Attorney-in-Fact. To more fully preserve and protect
     Lessor's rights under this Section, Lessee does hereby make, constitute and
     appoint Lessor its true and lawful attorney-in-fact, for it and in its
     name, place and stead to execute and deliver all such instruments and
     documents, and to do all such other acts and things, as Lessor may deem to
     be necessary or desirable to protect and preserve the rights granted under
     this Section. Lessee hereby grants to Lessor the full power and authority
     to appoint one or more substitutes to perform any of the acts that Lessor
     is authorized to perform under this Section, with a right to revoke such
     appointment of substitution at Lessor's pleasure. The power of attorney
     granted pursuant to this Section is coupled with an interest and therefore
     is irrevocable. Any person dealing with Lessor may rely upon the
     representation of Lessor relating to any authority granted by this power of
     attorney, including the intended scope of the authority, and may accept the
     written certificate of Lessor that this power of attorney is in full force
     and effect. Photographic or other facsimile reproductions of this executed
     Lease may be made and delivered by Lessor, and may be relied upon by any
     person to the same extent as though the copy were an original. Anyone who
     acts in reliance upon any representation or certificate of Lessor, or upon
     a reproduction of this Lease, shall not be liable for permitting Lessor to
     perform any act pursuant to this power of attorney. Notwithstanding the
     foregoing, Lessor covenants with Lessee that Lessor shall refrain from
     exercising the power of attorney granted hereby except in the case of an
     Event of Default hereunder or in the event of a default, which, in Lessor's
     reasonable judgment, may lead to the suspension or revocation of any
     license of Lessee or of any sublessee.

     34.4 INTANGIBLES AND PERSONAL PROPERTY. Notwithstanding any other provision
of this Lease but subject to Articles 40 or 41 relating to the security interest
in favor of Lessor, Leased Personal Property shall not include goodwill nor
shall it include any other

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<PAGE>

intangible personal property that is severable from Lessor's "interests in real
property" within the meaning of Section 856(d) of the Code, or any similar or
successor provision thereto.

                                  ARTICLE XXXV

                             [INTENTIONALLY OMITTED]

                                  ARTICLE XXXVI

                                  MISCELLANEOUS

     36.1 COMPLIANCE WITH FACILITY MORTGAGE. Lessee covenants and agrees that it
will duly and punctually observe, perform and comply with all of the terms,
covenants and conditions (including, without limitation, covenants requiring the
keeping of books and records and delivery of Financial Statements and other
information) of any Facility Mortgage and that it will not directly or
indirectly, do any act or suffer or permit any condition or thing to occur,
which would or might constitute a default under a Facility Mortgage. Anything in
this Lease to the contrary notwithstanding, if the time for performance of any
act required of Lessee by the terms of a Facility Mortgage is shorter than the
time allowed by this Lease for performance of such act by Lessee, then Lessee
shall perform such act within the time limits specified in such Facility
Mortgage.

     36.2 SURVIVAL, CHOICE OF LAW. Anything contained in this Lease to the
contrary notwithstanding, all claims against, and liabilities of, Lessee or
Lessor arising prior to the date of expiration or termination of this Lease
shall survive such expiration or termination. If any term or provision of this
Lease or any application thereof is held invalid or unenforceable, the remainder
of this Lease and any other application of such term or provisions shall not be
affected thereby. Neither this Lease nor any provision hereof may be changed,
waived, discharged or terminated except by an instrument in writing and in
recordable form signed by Lessor and Lessee. All the terms and provisions of
this Lease shall be binding upon and inure to the benefit of the parties hereto
and their respective successors and assigns. The headings in this Lease are for
convenience of reference only and shall not limit or otherwise affect the
meaning hereof. This Lease shall be governed by and construed in accordance with
the laws of the State, except as to matters which, under applicable procedural
conflicts of laws rules require the application of laws of another State.

     LESSEE CONSENTS TO IN PERSONAM JURISDICTION BEFORE THE STATE AND FEDERAL
COURTS OF THE STATES OF OKLAHOMA AND AGREES THAT ALL DISPUTES CONCERNING THIS
LEASE BE HEARD IN THE STATE AND FEDERAL COURTS LOCATED IN THE STATE OF OKLAHOMA.
LESSEE AGREES THAT SERVICE OF PROCESS MAY BE EFFECTED UPON IT UNDER ANY METHOD
PERMISSIBLE UNDER THE LAWS OF THE STATE OF OKLAHOMA AND IRREVOCABLY WAIVES ANY
OBJECTION TO VENUE IN THE STATE AND FEDERAL COURTS OF THE STATE OF OKLAHOMA.

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<PAGE>

     36.3 LIMITATION ON RECOVERY. Lessee specifically agrees to look solely to
Lessor's interest in the Leased Properties for recovery of any judgment from
Lessor, it being specifically agreed that no constituent shareholder, officer or
director of Lessor shall ever be personally liable for any such judgment or for
the payment of any monetary obligation to Lessee. Furthermore, Lessor (original
or successor) shall never be liable to Lessee for any indirect, consequential,
special or punitive damages suffered by Lessee from whatever cause.

     36.4 WAIVERS. Lessee waives any defense by reason of any disability of
Lessee, and waives any other defense based on the termination of Lessee's
(including Lessee's successor's) liability from any cause. Lessee waives all
presentments, demands for performance, notices of nonperformance, protests,
notices of protest, notices of dishonor, and notices of acceptance, and waives
all notices of the existence, creation, or incurring of new or additional
obligations.

     36.5 CONSENTS. Whenever the consent or approval of Lessor is required
hereunder, Lessor may in its sole discretion and without reason withhold that
consent or approval unless otherwise specifically provided.

     36.6 COUNTERPARTS. This Lease may be executed in separate counterparts,
each of which shall be considered an original when each party has executed and
delivered to the other one or more copies of this Lease.

     36.7 RIGHTS CUMULATIVE. Except as provided herein to the contrary, the
respective rights and remedies of the parties specified in this Lease shall be
cumulative and in addition to any rights and remedies not specified in this
Lease.

     36.8 ENTIRE AGREEMENT. There are no oral or written agreements or
representations between the parties hereto affecting this Lease. This Lease
supersedes and cancels any and all previous negotiations, arrangements,
representations, brochures, agreements and understandings, if any, between
Lessor and Lessee.

     36.9 AMENDMENTS IN WRITING. No provision of this Lease may be amended
except by an agreement in writing signed by Lessor and Lessee.

     36.10 SEVERABILITY. If any provision of this Lease or the application of
such provision to any person, entity or circumstance is found invalid or
unenforceable by a court of competent jurisdiction, such determination shall not
affect the other provisions of this Lease and all other provisions of this Lease
shall be deemed valid and enforceable.

     36.11 ESTOPPEL CERTIFICATE. At any time and from time to time, Lessee
shall, without charge, within ten (10) days after request by Lessor, certify by
a written instrument executed and acknowledged by a duly authorized
representative of Lessee, addressed to Lessor and any mortgagee or purchaser, or
proposed mortgagee or proposed purchaser, or any other party, firm or
corporation specified by Lessor, as to the validity and status of this Lease, as
to the existence of any default on the part of any party hereunder, as to the
existence of any offsets,

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<PAGE>

counterclaims, or defenses thereto which may be alleged on the part of Lessee,
and as to any other matters which may be reasonably requested by Lessor.

     36.12 TIME OF THE ESSENCE. Except for the delivery of possession of the
Facilities to Lessee, time is of the essence of all provisions of this Lease of
which time is an element.

     36.13 LESSOR'S COSTS AND EXPENSES. Lessee shall be responsible for and
shall pay on demand by Lessor, all of Lessor's reasonable costs and expenses
incurred in connection with the negotiation and preparation of this Lease,
including without limitation, the reasonable fees and expenses of Lessor's
attorneys.

                                 ARTICLE XXXVII

                                     BROKERS

     37.1 COMMISSIONS. Lessee represents and warrants to Lessor that no real
estate commission, finder's fee or the like is due and owing to any person in
connection with this Lease. Lessee agrees to save, indemnify and hold Lessor
harmless from and against any and all claims, liabilities or obligations for
brokerage, finder's fees or the like in connection with this Lease or the
transactions contemplated hereby, asserted by any person on the basis of any
statement or act alleged to have been made or taken by Lessee.

                                  ARTICLE XVIII

                               MEMORANDUM OF LEASE

     38.1 MEMORANDUM OR SHORT FORM OF LEASE. Lessor and Lessee shall, promptly
upon the request of either, enter into a Memorandum or Short Form of Lease,
substantially in the form of EXHIBIT G with such modifications as may be
appropriate under the laws and customs of the States and in the customary form
suitable for recording under the laws of each of the States. Lessee shall pay
all costs and expenses of recording such memorandum or short form of this Lease.

                                  ARTICLE XXXIX

                               RECHARACTERIZATION

     39.1 RECHARACTERIZATION AS A SECURITY DOCUMENT. In the event that
notwithstanding the intent of Lessor, Lessee and Guarantor as set forth herein,
that this Lease be treated as a true lease for purposes of the UCC and other
applicable laws of the State, a court of competent jurisdiction recharacterizes
this Lease as a security document serving as collateral for a financing, the
additional provisions set forth in Article XL and Article XLI shall apply,
provided however, such application shall in no event otherwise diminish,
restrict or eliminate any of the Lessor's rights or remedies set forth in this
Lease or in any of the other documents executed in connection herewith, all of
the foregoing to remain in full force and effect for all purposes.

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<PAGE>

                                   ARTICLE XL

                             GRANT OF MORTGAGE LIEN

     40.1 GRANT OF LIEN AND SECURITY INTEREST; ASSIGNMENT OF RENTS. To secure to
the Lessor the performance by the Lessee of its covenants, agreements and
obligations under the Lease, Lessee hereby agrees as follows:

          40.1.1 Mortgage. Subject to the terms and conditions of the Lease, and
     in addition to all other rights and remedies of Lessor as contained herein
     or under applicable law, the Lessee does hereby mortgage, pledge, grant,
     bargain, sell, convey, assign, warrant, transfer and set over to the
     Lessor, WITH POWER OF SALE, to the extent permitted by applicable law: (i)
     all of the Lessee's right, title and interest, if any, in the Leased
     Properties, and (ii) all of the Lessee's right, title and interest in and
     to all proceeds of the conversion, whether voluntary or involuntary, of any
     of the above-described property into cash or other liquid claims,
     including, without limitation, all awards, payments or proceeds, including
     interest thereon, and the right to receive the same, which may be made as a
     result of casualty, any exercise of the right of eminent domain or deed in
     lieu thereof, the alteration of the grade of any street and any injury to
     or decrease in the value thereof, the foregoing collectively being referred
     to hereinafter as the "Security Property".

     TO HAVE AND TO HOLD the foregoing rights, interests and properties, and all
     rights, estates, powers and privileges appurtenant thereto, unto the
     Lessor, its successors and assigns, forever, for the uses and purposes
     herein expressed, but not otherwise.

          40.1.2 Security Interest. Subject to the terms and conditions of the
     Lease, the Lessee hereby grants to the Lessor a security interest in the
     Lessee's interest, if any, in that portion of the Security Property (the
     "UCC Property") subject to the Uniform Commercial Code of the state in
     which the Leased Properties are located (the "UCC"). This Lease shall also
     be deemed to be a security agreement and a financing statement filed as a
     fixture filing pursuant to 12A O.S. Section 1-9-502 and shall support any
     financing statement showing the Lessor's interest as a secured party with
     respect to any portion of the UCC Property described in such financing
     statement. The Lessee agrees, at its sole cost and expense, to execute,
     deliver and file from time to time such further instruments as may be
     requested by the Lessor to confirm and perfect the lien of the security
     interest in the collateral described in this Lease.

          40.1.3 Assignment of Leases and Rents. The Lessee hereby irrevocably
     assigns, conveys, transfers and sets over unto the Lessor (subject,
     however, to the Lease and the rights of the Lessee thereunder and
     hereunder) all and every part of the rents, issues and profits that may
     from time to time become due and payable on account of any and all
     subleases or other occupancy agreements now existing, or that may hereafter
     come into existence with respect to the Leased Properties or any part
     thereof, including any

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<PAGE>

     guaranties of such subleases or other occupancy agreements. Upon request of
     the Lessor, the Lessee shall execute and cause to be recorded, at its
     expense, supplemental or additional assignments of any subleases or other
     occupancy agreements, of the Leased Properties. Upon the occurrence and
     continuance of a Event of Default, the Lessor is hereby fully authorized
     and empowered in its discretion (in addition to all other powers and rights
     herein granted), and subject to the Lease and the rights of the Lessee
     thereunder and hereunder, to apply for and collect and receive all such
     rents, issues and profits and to enforce any guaranty or guaranties, and
     all money so received under and by virtue of this assignment shall be held
     and applied as further security for the payment of the indebtedness secured
     hereby and to assure the performance by the Lessee of its covenants,
     agreements and obligations under the Lease.

     40.2 REMEDIES. Upon the occurrence and continuance of an Event of Default:

          40.2.1 Power of Sale Foreclosure. The Lessor shall have the power and
     authority, to the extent provided by law, after proper notice and lapse of
     such time as may be required by the Oklahoma Power of Sale Mortgage
     Foreclosure Act, 46 O.S. Section 40-49, as amended from time to time (the
     "Act"), to sell the Security Property at the time and place of sale fixed
     by the Lessor in said notice of sale, either as a whole, or in separate
     lots or parcels and in such order as the Lessor may elect, at auction to
     the highest bidder for cash in lawful money of the United States payable at
     the time of sale, all in accordance with the Act and any other applicable
     laws of the jurisdiction in which the Leased Properties are located, it
     being acknowledged that A POWER OF SALE HAS BEEN GRANTED IN THIS
     INSTRUMENT. A POWER OF SALE MAY ALLOW THE LESSOR TO TAKE THE SECURITY
     PROPERTY AND SELL IT WITHOUT GOING TO COURT IN A FORECLOSURE ACTION UPON
     THE OCCURRENCE AND CONTINUANCE OF AN EVENT OF DEFAULT BY THE LESSEE.

          40.2.2 Judicial Foreclosure. The Lessor may proceed by a suit or suits
     in equity or at law, whether for a foreclosure hereunder, or for the sale
     of the Security Property, or, subject to the terms and conditions of the
     Lease, against the Lessee for the Rent, or for the specific performance of
     any covenant or agreement herein contained or in aid of the execution of
     any power herein granted, or for the appointment of a receiver pending any
     foreclosure hereunder or the sale of the Security Property, or for the
     enforcement of any other appropriate legal or equitable remedy.

          40.2.3 Appointment of Receiver. Without regard to the Lessor's
     election of nonjudicial power of sale foreclosure or judicial foreclosure,
     the Lessor shall be entitled to the appointment of a receiver by any court
     of competent jurisdiction, without notice and without regard to the
     sufficiency or value of any security for the indebtedness secured hereby or
     the solvency of any party bound for its payment. The receiver shall have
     all of the rights and powers permitted under the laws of the state within
     which the Leased Properties are located.

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<PAGE>

          40.2.4 Waiver of Appraisement Appraisement of the Leased Properties is
     hereby waived or not waived at the option of the Lessor, such option to be
     exercised at or prior to the time judgment is rendered in any judicial
     foreclosure.

          40.2.5 Additional Remedies. It is the intent of the parties hereto
     that, upon the occurrence and continuance of an Event of Default, the
     Lessor shall have the remedies provided for in this Section 40.2; provided,
     however, that (i) in lieu of the remedies provided for in this Lease, the
     Lessor, at its election, may require the Lessee to purchase the Leased
     Properties and, in the event that the Lessee purchases the Leased
     Properties as provided in Section 16.4 of this Lease, the remedies set
     forth herein shall not be available to the Lessor with respect to such
     Event of Default, and (ii) in the event that, notwithstanding the intention
     of the parties, a court of competent jurisdiction determines that the
     remedies in this Section 40.2 are unenforceable, the Lessor shall have, as
     a result of such determination, in lieu of the remedies in this Section
     40.2, any and all of the other remedies provided for in Article 16 of this
     Lease. To the extent not in conflict with applicable law or the Lessee's
     obligations thereunder, the parties acknowledge and agree that the
     provisions of 11 U.S.C. Section 502(b)(6) are not applicable to the
     transactions contemplated by this Lease.

          40.2.6 Cure by Purchase of Leased Properties. Notwithstanding anything
     to the contrary contained herein, the Lessee may cure any Event of Default
     affecting or relating to the Leased Properties by purchasing the Leased
     Properties as provided in Section 16.4 of this Lease.

                                   ARTICLE XLI

                           GRANT OF SECURITY INTEREST

     41.1 GRANT OF SECURITY INTEREST. The Lessee hereby pledges, assigns and
grants to the Lessor a security interest in and to the Collateral to secure the
prompt and complete payment and performance of all of Lessee's covenants,
agreements and obligations under this Lease.

     41.2 UCC REPRESENTATIONS AND WARRANTIES. Lessee and Guarantor represent and
warrant to the Lessor that:

          41.2.1 Authorization, Validity and Enforceability. Lessee has good and
     valid power to grant a security interest hereunder, free and clear of all
     Encumbrances except for Encumbrances permitted under Section 41.3.6, and
     has full power and authority to grant to the Lessor the security interest
     in such Collateral pursuant hereto. When financing statements have been
     filed in the appropriate offices against the Lessee in the locations listed
     on EXHIBIT P, the Lessor will have a fully perfected, first priority,
     security interest in that Collateral in which a security interest may be
     perfected by filing, subject only to Encumbrances permitted under Section
     41.3.6.

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<PAGE>

          41.2.2 Conflicting Laws and Contracts. Neither the execution and
     delivery by the Lessee of this Lease, the creation and perfection of the
     security interest in the Collateral granted hereunder, nor compliance with
     the terms and provisions hereof will violate any law, rule, regulation,
     order, writ, judgment, injunction, decree or award binding on any Lessee or
     Lessee's articles or certificate of incorporation or by-laws, partnership
     agreements, or operating agreements, as the case may be, the provisions of
     any indenture, instrument or agreement to which Lessee is a party or is
     subject, or by which it, or its property, is bound, or conflict with or
     constitute a default thereunder, or result in the creation or imposition of
     any Encumbrance pursuant to the terms of any such indenture, instrument or
     agreement.

          41.2.3 Type and Jurisdiction of Organization. The organizational type
     and jurisdiction for Lessee and Guarantor are set forth in the Preamble.

          41.2.4 Principal Location. Each of the Lessee's and Guarantor's
     mailing address and the location of its place of business (if it has only
     one) or its chief executive office, is disclosed in EXHIBIT P; Lessee has
     no other places of business except those set forth in EXHIBIT P.

          41.2.5 Property Locations. All of the Collateral is located solely in
     Tulsa, Oklahoma, on or connected with the Land or the Leased Improvements.

          41.2.6 No Other Names. Lessee has not conducted business under any
     name except the name in which it has executed this Lease, which is the
     exact name as it appears in the Lessee's organizational documents, as
     amended, as filed with the Lessee's jurisdiction of organization.

          41.2.7 No Financing Statements. No financing statement describing all
     or any portion of the Collateral which has not lapsed or been terminated
     naming the Lessee as debtor has been filed in any jurisdiction except (i)
     financing statements naming the Lessor as the secured party, and (ii) as
     permitted by Section 41.3.6. None of the Equipment is covered by any
     certificate of title.

          41.2.8 Federal Employer Identification Number. The Federal employer
     identification numbers for both Lessee and Guarantor are set forth on
     EXHIBIT P.

     41.3 UCC COVENANTS. The following covenants shall apply to the Collateral.

          41.3.1 Inspection. Lessee and Guarantor will permit the Lessor, by its
     representatives and agents (i) to inspect the Collateral, (ii) to examine
     and make copies of the records of the Lessee relating to the Collateral and
     (iii) to discuss the Collateral and the related records of Lessee and
     Guarantor with, and to be advised as to the same by, the Lessee's and
     Guarantor's respective officers and employees, all at such reasonable times
     and intervals as the Lessor may determine, and all at the Lessee's and
     Guarantor's expense.

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<PAGE>

          41.3.2 Taxes. Lessee and Guarantor will pay or cause to be paid when
     due all taxes, assessments and governmental charges and levies upon the
     Collateral, except those which are being contested in good faith by
     appropriate Proceedings and with respect to which no Encumbrance exists.

          41.3.3 Records and Reports; Notification of Default. Lessee will
     maintain complete and accurate books and records with respect to the
     Collateral, and furnish to the Lessor such reports relating to the
     Collateral as the Lessor shall from time to time request. Each of the
     Lessee and Guarantor will give prompt notice in writing to the Lessor of
     the occurrence of any Event of Default and of any other development,
     financial or otherwise, which might materially and adversely affect the
     Collateral.

          41.3.4 Financing Statements and Other Actions; Defense of Title. Both
     Lessee and Guarantor hereby authorize the Lessor to file and if requested
     will execute and deliver to the Lessor all financing statements and other
     documents and take such other actions as may from time to time be requested
     by the Lessor in order to maintain a first perfected security interest in
     and, if applicable, control of, the Collateral. Lessee and Guarantor will
     take any and all actions necessary to defend title to the Collateral
     against all persons and to defend the security interest of the Lessor in
     the Collateral and the priority thereof against any Encumbrance not
     expressly permitted hereunder.

          41.3.5 Disposition of Collateral. Lessee will not sell, lease or
     otherwise dispose of the Collateral except (i) prior to the occurrence of
     an Event of Default, dispositions specifically permitted pursuant to this
     Lease, (ii) until such time following the occurrence of an Event of Default
     as Lessee receives a notice from the Lessor instructing the Lessee to cease
     such transactions, sales or leases of Inventory in the ordinary course of
     business, and (iii) until such time as Lessee receives a notice from the
     Lessor, proceeds of Inventory collected in the ordinary course of business.

          41.3.6 Encumbrances. Neither Lessee nor Guarantor will create, incur,
     or suffer to exist any Encumbrance on the Collateral except (i) the
     security interest created by this Lease, and (ii) Permitted Encumbrances.

          41.3.7 Change of Name or Mailing Address. Lessee will not (i) change
     its name or taxpayer identification number or (ii) change its mailing
     address, unless Lessee shall have given the Lessor not less than thirty
     (30) days' prior written notice of such event or occurrence and the Lessor
     shall have either (x) determined that such event or occurrence will not
     adversely affect the validity, perfection or priority of the Lessor's
     security interest in the Collateral, or (y) taken such steps (with the
     cooperation of Lessee and Guarantor to the extent necessary or advisable)
     as are necessary or advisable to properly maintain the validity, perfection
     and priority of the Lessor's security interest in the Collateral.

          41.3.8 Other Financing Statements. Lessee will not sign or authorize
     the signing on its behalf of the filing of any financing statement naming
     it as debtor covering all or any portion of the Collateral, except as
     permitted by Section 41.3.6.

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<PAGE>

          41.3.9 Maintenance of Goods. Lessee will do all things necessary to
     maintain, preserve, protect and keep the Inventory and the Equipment in
     good repair and working condition.

     41.4 ACCELERATION AND REMEDIES. Upon the acceleration of the Rent pursuant
to the terms hereof, the Lessor may exercise any or all of the following rights
and remedies:

          41.4.1 UCC Remedies. Those rights and remedies available to a secured
     party under the UCC (whether or not the UCC applies to the affected
     Collateral) or under any other applicable law when a debtor is in default
     under a security agreement.

          41.4.2 Disposal. Without notice except as specifically provided
     elsewhere in this Lease, sell, lease, assign, grant an option or options to
     purchase or otherwise dispose of the Collateral or any part thereof in one
     or more parcels at public or private sale, for cash, on credit or for
     future delivery, and upon such other terms as the Lessor may deem
     commercially reasonable.

          41.4.3 Compliance with Law. The Lessor may comply with any applicable
     state or federal law requirements in connection with a disposition of the
     Collateral, and compliance will not be considered to adversely affect the
     commercial reasonableness of any sale of the Collateral.

     41.5 OBLIGATIONS UPON DEFAULT. Upon the request of the Lessor after the
occurrence of an Event of Default, both Lessee and Guarantor will:

          41.5.1 Assembly of Collateral. Assemble and make available to the
     Lessor the Collateral and all records relating thereto at any place or
     places specified by the Lessor.

          41.5.2 Lessor Access. Permit the Lessor, by the Lessor's
     representatives and agents, to enter any premises where all or any part of
     the Collateral, or the books and records relating thereto, or both, are
     located, to take possession of all or any part of the Collateral and to
     remove all or any part of the Collateral.

     41.6 ADDITIONAL UCC PROVISIONS. The following additional provisions shall
apply to the Collateral:

          41.6.1 Notice of Disposition of Collateral; Condition of Collateral.
     Notice of the time and place of any public sale or the time after which any
     private sale or other disposition of all or any part of the Collateral
     shall be deemed reasonable if sent to the Lessee at least ten (10) days
     prior to (i) the date of any such public sale or (ii) the time after which
     any such private sale or other disposition may be made. Lessor shall have
     no obligation to clean-up or otherwise prepare the Collateral for sale.

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<PAGE>

          41.6.2 Lessor Performance of Lessee Obligations. Without having any
     obligation to do so, the Lessor may perform or pay any obligation which
     Lessee has agreed to perform or pay in this Lease and Lessee and Guarantor
     shall reimburse the Lessor for any amounts paid by the Lessor pursuant to
     this Section 41.6.2.

          41.6.3 Authorization for Lessor to Take Certain Action. Lessee
     irrevocably authorizes the Lessor at any time and from time to time in the
     sole discretion of the Lessor and appoints the Lessor as its
     attorney-in-fact (i) to execute on behalf of Lessee and to file financing
     statements necessary or desirable in the Lessor's sole discretion to
     perfect and to maintain the perfection and priority of the Lessor's
     security interest in the Collateral, (ii) to indorse and collect any cash
     proceeds of the Collateral, (iii) to file a carbon, photographic or other
     reproduction of this Lease or any financing statement with respect to the
     Collateral as a financing statement and to file any other financing
     statement or amendment of a financing statement (which does not add new
     collateral or add a debtor) in such offices as the Lessor in its sole
     discretion deems necessary or desirable to perfect and to maintain the
     perfection and priority of the Lessor's security interest in the
     Collateral, (iv) to apply the proceeds of any Collateral received by the
     Lessor to the Rent, and (v) to discharge past due taxes, assessments,
     charges, fees or Encumbrances on the Collateral (except for such
     Encumbrances as are specifically permitted hereunder), and Lessee and
     Guarantor agree to reimburse the Lessor on demand for any payment made or
     any expense incurred by the Lessor in connection therewith, provided that
     this authorization shall not relieve Lessee or Guarantor of any obligations
     under this Lease.

          41.6.4 Dispositions Not Authorized. Neither Lessee or Guarantor is
     authorized to sell or otherwise dispose of the Collateral except as set
     forth in Section 41.3.5 and notwithstanding any course of dealing between
     Lessee and Guarantor, and Lessor or other conduct of the Lessor, no
     authorization to sell or otherwise dispose of the Collateral (except as set
     forth in Section 41.3.5) shall be binding upon the Lessor unless such
     authorization is in writing signed by the Lessor.

                                  ARTICLE XLII

                                PURCHASE OPTIONS

     42.1 OPTION TO PURCHASE. For good and valuable consideration the receipt
and sufficiency of which are hereby acknowledged, and in addition to Lessor's
right to require Lessee to purchase the Leased Properties as set forth in
Section 16.4, Lessor hereby grants to Lessee the option to purchase the Leased
Properties or portions thereof, which option may be exercised by Lessee at any
time during the Terms, all pursuant to the terms and conditions set forth on
EXHIBIT O.

     42.2. PUT OPTION OF LESSOR. For good and valuable consideration the receipt
and sufficiency of which are hereby acknowledged, Lessee grants to Lessor the
right for Lessor to require Lessee to purchase the Leased Properties or portions
thereof, either (i) any time after the date which is ninety (90) days prior to
the Realty Expiration Date, or (ii) otherwise pursuant to

                                       69
<PAGE>

the provisions of Section 14.8, subject to the same terms, covenants and
conditions applicable to Lessee's Option to Purchase as set forth in Section
42.1 and as described on EXHIBIT O.

     42.3. TERMINATION OF LEASE. In the event of Exercise of Option as set forth
herein and the acquisition of Leased Properties by Lessee, this Lease shall
terminate effective as of the closing of such purchase.

                             SIGNATURE PAGES FOLLOW

                                       70
<PAGE>

     IN WITNESS WHEREOF, the parties hereto have respectively executed this
Lease effective as of the Effective Date.

LESSOR                                 WILLIAMS HEADQUARTERS BUILDING
                                       COMPANY, A Delaware Corporation

                                       By:
                                           -------------------------------------
                                       Name:
                                             -----------------------------------
                                       Title:
                                              ----------------------------------

LESSEE                                 WILLIAMS TECHNOLOGY CENTER, LLC,
                                       A Delaware Limited Liability Company

                                       By:
                                           -------------------------------------
                                       Name:
                                             -----------------------------------
                                       Title:
                                              ----------------------------------

GUARANTOR                              WILLIAMS COMMUNICATIONS, LLC,
                                       A Delaware Limited Liability Company

                                       By:
                                           -------------------------------------
                                       Name:
                                             -----------------------------------
                                       Title:
                                              ----------------------------------

WCG - FOR THE LIMITED PURPOSE OF SECTION 8.2, 8.3, ARTICLE XVII, AND SECTION
23.2

                                       WILLIAMS COMMUNICATIONS GROUP, INC.
                                       A DELAWARE CORPORATION

                                       BY:
                                           -------------------------------------
                                       NAME:
                                             -----------------------------------
                                       TITLE:
                                              ----------------------------------

                                       71
<PAGE>

EXHIBIT A       -        Center Parcel Real Property Description
EXHIBIT B       -        Parking Structure Parcel Property Description
EXHIBIT C       -        Credit Agreement
EXHIBIT D       -        Lessee's Certificate
EXHIBIT E       -        Permitted Encumbrances
EXHIBIT F       -        Consent and Non-Disturbance Agreement
EXHIBIT G       -        Memorandum or Short Form of Lease
EXHIBIT H       -        Guaranty
EXHIBIT I       -        Interest Rate Calculation
EXHIBIT J       -        Realty Base Rent Computation
EXHIBIT K       -        Category 1 FF&E Tangible Personal Property Description
EXHIBIT L       -        Category 1 FF&E Base Rent Computation
EXHIBIT M       -        Category 2 FF&E Tangible Personal Property Description
EXHIBIT N       -        Category 2 FF&E Base Rent Computation
EXHIBIT O       -        Option to Purchase/Put Option Terms
EXHIBIT P       -        UCC Information

SCHEDULE 22.2   -        Sublease Parties

                                       72
<PAGE>
EXECUTION COPY

                                    EXHIBIT I

                            Interest Rate Calculation

The following definitions shall apply to this EXHIBIT I:

         "ABR", when used herein, refers to interest at a rate determined by
reference to the Alternate Base Rate.

         "Applicable Margin" means, for any day, (i) the applicable rate per
annum set forth below under the caption "Eurodollar Spread" or "ABR Spread", as
the case may be, based upon the Guarantor's Bank Facility Rating set by S&P and
Moody's, respectively, applicable on such date plus (ii) the applicable rate per
annum set forth below under the caption "Leverage Premium", unless the Total
Leverage Ratio, as determined by reference to the financial statements delivered
to the Lessor in respect of the most recently ended fiscal quarter of WCG, is
less than 6:00 to 1:00.

         "Eurodollar", when used herein, refers to interest at a rate determined
by reference to the Adjusted LIBO Rate.

         "Facilities" means the Term Facility, the Revolving Facility, the
Incremental Facility and each Additional Incremental Facility, all as defined in
the Credit Agreement.

         "LIBO Rate" means, with respect to any Eurodollar Rate, the rate
appearing on Page 3750 of the Telerate Service (or on any successor or
substitute page of such Service, or any successor to or substitute for such
Service, providing rate quotations comparable to those currently provided on
such page of such Service, as determined by the Lessor from time to time for
purposes of providing quotations of interest rates applicable to dollar deposits
in the London interbank market) at approximately 11:00 a.m., London time, two
(2) Business Days prior to the first day of each calendar month, as the rate for
dollar deposits with a maturity of thirty (30) days. In the event that such rate
is not available at such time for any reason, then the "LIBO Rate" shall be the
rate (rounded upwards, if necessary, to the next 1/16 of 1%) at which dollar
deposits of $5,000,000 and for a maturity of thirty (30) days are offered by the
principal London office of the CitiBank, N.A., in immediately available funds in
the London interbank market at approximately 11:00 a.m., London time, two (2)
Business Days prior to the first day of each calendar month. In either case, the
applicable LIBO Rate shall be effective for the calendar month next succeeding
the date of such determination.

         "Moody's" means Moody's Investors Service, Inc.

         "S&P" means Standard & Poor's Ratings Services, a division of the
McGraw Hill Companies.

                                       91
<PAGE>

At Lessee's option, ABR plus Applicable Margin or LIBO Rate plus Applicable
Margin (the "Rate") as determined from time to time by S&P or by Moody's based
on Guarantor's Facilities Rating in accordance with the grid below:

<Table>
<Caption>
                                   FACILITIES RATING OF                                EURODOLLAR       LEVERAGE
                                        GUARANTOR                     ABR SPREAD         SPREAD          PREMIUM
                                   --------------------               ----------       ----------        -------
<S>                          <C>                                      <C>              <C>              <C>
       Level I                   BBB- and Baa3 or higher                 0.50%            1. 50%           .25%
       Level II                        BB+ and Ba1                      0.875%            1.875%           .25%
      Level III                         BB and Ba2                       1.25%             2.25%           .25%
       Level IV                        BB- and Ba3                       1.50%             2.50%           .25%
       Level V               Lower than BB- or lower than Ba3            1.75%             2.75%           .25%
</Table>

         For purposes of the foregoing (i) if neither S&P nor Moody's or any
replacement or successor facility of similar size shall have in effect a rating
for the Facilities, then the Applicable Margin shall be the rate set forth in
Level V, (ii) if either S&P or Moody's, but not both S&P and Moody's, shall have
in effect a rating for the Facilities, then the Applicable Margin shall be based
on such rating, (iii) if the ratings established by S&P and Moody's for the
Facilities shall fall within different Levels, then the Applicable Margin shall
be based on the lower of the two ratings, (iv) if the ratings established by S&P
and Moody's for the Facilities shall fall within the same Level, then the
Applicable Margin shall be based on that Level and (v) if the ratings
established by S&P and Moody's for the Facilities shall be changed (other than
as a result of a change in the rating system of S&P or Moody's), such change
shall be effective as of the date on which it is first announced by the
applicable rating agency. Each change in the Applicable Margin shall apply
during the period commencing on the effective date of such change and ending on
the date immediately preceding the effective date of the next such change.

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<PAGE>
EXECUTION COPY

                                    EXHIBIT J

                          Realty Base Rent Computation

Monthly Realty Base Rent to be an amount as would be necessary to amortize
$168,892,596 (the "Realty Base Rent Principal") on a straight-line basis over a
period of four hundred and eighty (480) months plus interest (the "Realty Base
Rent Interest") calculated at the Rate for the first thirty-six (36) months
after the Commencement Date and on a straight-line basis over a period of two
hundred and four (204) months plus interest calculated at the Rate for the
remaining balance thereafter, subject however to the adjustments made with
respect to levels two (2) and three (3) of the Center as set forth in Section
3.1. On the Realty Expiration Date, a final payment of Realty Base Rent in the
amount computed by taking what would be the remaining Realty Base Rent Principal
as amortized pursuant to this EXHIBIT J, as of the Realty Expiration Date.

                                       93

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