SEVENTH AMENDMENT TO LEASE



         THIS SEVENTH  AMENDMENT TO LEASE (the  "Amendment") is made and entered
into this  ______ day of , 1997,  by and between  LAFP-SF,  Inc.,  successor  in
interest to The Prudential Insurance Company Of America ("Landlord"),  having an
office c/o Lowe Enterprises  Colorado,  Inc., 1475 Lawrence  Street,  Suite 210,
Denver,  Colorado 80202, and Data Transmission  Network Corporation  ("Tenant"),
having an office at 9110 West Dodge Road, Suite 200, Omaha, Nebraska 68114.


                                    RECITALS

A.       The  Prudential  Insurance  Company  of America  and Data  Transmission
         Network  Corporation entered into that certain Lease dated as of May 2,
         1995, for Suites #175A, #110, #200, #300, #301, #310, #320, #325, #340,
         #360,  #362, and #100  containing  75,931 rentable square feet (RSF) in
         the Building known as Embassy  Plaza,  located at 9110 West Dodge Road,
         Omaha, Nebraska ("the Premises").

B.       Subsequently,  The  Prudential  Insurance  Company Of America  and Data
         Transmission  Network  Corporation  executed a First Amendment To Lease
         dated September 29, 1995, a Second  Amendment To Lease dated January 5,
         1996, a Third  Amendment To Lease dated  January 5, 1996,  and a Fourth
         Amendment To Lease between LAFP-SF,  Inc. and Tenant dated December 23,
         1996,  a Fifth  Amendment  To Lease  dated  July 7,  1997,  and a Sixth
         Amendment To Lease dated July 7, 1997.  The combined terms of the Lease
         and subsequent  Amendments  shall herein be referred to as the "Lease".
         Under the Lease the Premises consists of a total of 92,680 RSF.

C.       Landlord and Tenant  acknowledge that the surface parking for the
         Building is overburdened,  in part as a result of Tenant's use thereof.

D.       Landlord  intends to construct  additional  parking  facilities to ser-
         vice Tenant and other tenants in the Building subject to the terms and
         conditions contained below.

E.       All capitalized terms not defined herein shall have the meanings as-
         cribed to them in the Lease.

         NOW,  THEREFORE,  in consideration of the foregoing  promises and other
good and  valuable  considerations,  the  receipt and  sufficiency  of which are
hereby acknowledged, the parties hereto covenant and agree as follows:

1.       Premises.  Effective September 16, 1997, the Premises  shall be expand-
         ed to  include  Suite  130,  measuring  1,180 RSF as shown on the floor
         plans attached  hereto,  marked Exhibit "A" (the "Expansion  Premises")
         and by this  reference made a part hereof.  Notwithstanding  the above,
         both Tenant and Landlord  understand that E.L.H.,  Inc. / d.b.a. Todays
         Temporary   currently  leases  Suite  130,  with  such  lease  expiring
         approximately  September 15, 1997. Should E.L.H.,  Inc. / d.b.a. Todays
         Temporary  holdover  and not vacate  Suite 130 by  September  15, 1997,
         Landlord will make  reasonable  efforts to pursue its legal remedies to
         have E.L.H.,  Inc. / d.b.a. Todays Temporary removed from the space. If
         the Expansion Premises is delivered to Tenant after September 16, 1997,
         Landlord and Tenant shall execute a  Commencement  Date  Certificate in
         the form attached hereto as Exhibit "C", confirming Landlord's delivery
         of the Expansion Premises and commencement of the Lease with respect to
         the Expansion Premises.

2.       Term.  The term of the Lease with  respect to the  Expansion  Premises
         identified in Paragraph 1 above shall commence  September 16, 1997, and
         terminate upon termination of the Lease.

                                       1

                                     - 72 -
<PAGE>


3.       Base  Rent.  Tenant  shall  pay as Base Rent for the  Expansion  Pre-
         mises during the Term the sum of One Hundred Fifty-Four Thousand,  Nine
         Hundred and One Dollars,  and Nine Cents ($154,901.09)  payable monthly
         as follows:

              September 16, 1997 - May 31, 2001        $1,622.50 / Month
              June 1, 2001 - May 31, 2005              $1,720.83 / Month

4.       Adjustment Rent.  Effective upon  commencement of the Term with respect
         to the  Expansion  Premises,  Tenant  shall  pay  Adjustment  Rent with
         respect to the  Expansion  Premises  in  accordance  with the terms and
         conditions  contained in Paragraph 2 of the Lease, except that the Base
         Expense Year and Base Tax Year with respect to the  Expansion  Premises
         herein shall be the calendar year 1997.

5.       Tenant  Improvements.  Landlord  shall  provide  a  tenant  improvement
         allowance of up to $11,800.00 to be applied toward the cost of Tenant's
         required building improvements.  All improvements shall be performed in
         accordance with the Tenant  Improvement Work Schedule  attached hereto,
         marked as Exhibit "B", and by this reference made a part hereof.

6.       Tenant's  Proportionate  Share.  The schedule for  Tenant's  Propor-
         tionate  Share with space  having a Base Expense Year and Base Tax Year
         of 1997, shall be revised to reflect the incorporation of the Expansion
         Premises as follows:

         August 1, 1997 - September 15, 1997     3.45% (4,544 RSF / 131,740 RSF)
         September 16, 1997 - May 31, 2005       4.34% (5,724 RSF / 131,740 RSF)

7.       Effect of  Agreement.  Except as  herein  specifically  provided,  the
         terms and  conditions  of the Lease  shall  continue  in full force and
         effect.

8.       This  Amendment  shall be binding upon and inure to the benefit of the
         parties hereto, their successors and assigns.

9.       The parties hereto hereby reaffirm and ratify all covenants,  represen-
         tations and warranties in the Lease as amended by this Amendment.

                                       2

                                     - 73 -
<PAGE>


         IN WITNESS WHEREOF, Landlord and Tenant have executed this Amendment as
of the day and year first above written.


Tenant:                                         Landlord:

Data Transmission Network Corporation,          LAFP-SF, Inc.
a Delaware corporation

                                                By:  Lowe Enterprises Investment
                                                     Management, Inc.
By:                                             Its:  Authorized Agent
   -----------------------------------

Its:                                            By:
    ----------------------------------             -----------------------------


                                                Its:
                                                    ----------------------------

                                       3

                                     - 74 -
<PAGE>

EXHIBIT "B" to be made a part of a Seventh  Amendment To Lease between  LAFP-SF,
INC.  (Landlord),  and DATA TRANSMISSION NETWORK CORPORATION  (Tenant),  dated ,
1997 (Page 1 of 2)



                        TENANT IMPROVEMENTS WORK SCHEDULE
                        ---------------------------------



                                    ARTICLE I
                       Landlord's Construction Obligations
                       -----------------------------------

     Landlord  shall have no  construction  obligations  under  this  Amendment.
Tenant accepts the Expansion  Premises in an "as is" condition,  with all faults
and  with  the  understanding  that  it  shall  be  responsible  for any and all
improvements required for its occupancy and use in accordance with Article II of
this Exhibit "B".



                                   ARTICLE II
                       Construction of Tenant Improvements
                       -----------------------------------

     Tenant  shall  have the right to place  partitions  and  fixtures  and make
improvements or other  alterations in the Expansion  Premises in accordance with
the  provisions of Paragraph 9 of the Lease.  Landlord  shall  provide  Tenant a
tenant finish allowance of up to Eleven  Thousand,  Eight Hundred Dollars and No
Cents  ($11,800.00)  to be applied  toward the cost of any such  tenant-provided
improvements as follows:

     1. The tenant finish allowance shall be paid in periodic installments,  not
more frequently than once per month,  equal to the total of the  contractor's or
consultant's  invoice amounts for improvements  made to the Expansion  Premises,
excluding   any   furnishings   or  business   equipment   (such  as  computers,
satellite/microwave  dish, office  equipment,  etc.), as submitted by Tenant and
verified to Landlord's  reasonable  satisfaction;  provided,  however, that such
payments  will be made only if Tenant is not then in Default  under the terms of
this Lease and invoices are  accompanied  by lien waivers in the amount equal to
that of the  invoices.  The  tenant  finish  allowance  shall be  allocated  and
distributed subject to the provisions of this Exhibit "B" as follows:

        September 16, 1997 - September 15, 1998      Up To $11,800.00

     2. Upon the earlier of the end date  identified in the allocation  schedule
specified  in  Paragraph  1  above,  or  the  satisfaction  of  all  obligations
associated  with the  tenant  improvements  covered  under  this  Article II and
receipt of the  associated  lien waivers for the work,  the Tenant shall forfeit
any unused  portion of the allowance.  Any requests for payment  received by the
Landlord after the above  specified end date, will be returned to the Tenant and
will be the obligation and sole responsibility of the Tenant.

     3. In addition to the provisions set forth in Paragraph 9 of the Lease,
Tenant's  contractor shall (and its contract shall so provide):

         (a)  conduct  its  work  in  such a  manner  so as not to  unreasonably
              interfere with other tenants in the Building, Building operations,
              or any other  construction  occurring on or in the Building or the
              Premises;

         (b)  execute  a set  of and  comply  with  all  rules  and  regulations
              relating to the  construction  activities in or on the Building as
              may be reasonably promulgated from time to time by Landlord or its
              agents;

         (c)  maintain such insurance  (such as general  liability and workman's
              compensation)  and bonds (such as performance  and  completion) in
              force and effect as may be reasonably  requested by Landlord or as
              required by  applicable  law (but in any event said bonds shall be
              in amounts  equal to the full value or cost of the work being done
              by the Tenant contractor);

                                       4

                                     - 75 -
<PAGE>

EXHIBIT "B" to be made a part of a Seventh  Amendment To Lease between  LAFP-SF,
INC.  (Landlord),  and DATA TRANSMISSION NETWORK CORPORATION  (Tenant),  dated ,
1997. (Page 2 of 2)

         (d)  be  responsible  for reaching an agreement  with  Landlord and its
              agents as to the terms and  conditions  for all  contractor  items
              relating to the conducting of its work,  including but not limited
              to, those matters relating to hoisting,  systems interfacing,  use
              of  temporary  utilities,  storage  of  materials,   placement  of
              dumpsters,  access  to the  Premises  and  the  Building,  and the
              purchase and return of Building standard materials.

         (e)  Upon  completion  of any tenant  improvements,  Tenant shall
              promptly  furnish  Landlord  with sworn  owner's and  contractors'
              statements  and full and final  waivers of lien covering all labor
              and  materials  included in such  improvements.  Tenant  shall not
              permit any  mechanic's  lien to be filed against the Building,  or
              any part thereof,  arising out of any  improvement  performed,  or
              alleged to have been performed,  by or on behalf of Tenant. If any
              such lien is filed,  Tenant shall within ten (10) days  thereafter
              have such lien released of record or deliver to Landlord a bond in
              form,  amount,  and issued by a surety  satisfactory  to Landlord,
              indemnifying  Landlord against all costs and liabilities resulting
              from  such  lien  and the  foreclosure  or  attempted  foreclosure
              thereof.  If  Tenant  fails to have such  lien so  released  or to
              deliver such bond to Landlord, Landlord, without investigating the
              validity of such lien,  may pay or discharge the same;  and Tenant
              shall  reimburse  Landlord  upon  demand for the amount so paid by
              Landlord, including Landlord's expenses and attorney's fees.

     4. Landlord shall have the right to approve all  subcontractors  to be used
by the Tenant's contractor, which approval shall not be unreasonably withheld as
long as such subcontractors satisfy the requirements of this Article II.

     5.  Tenant  shall  indemnify  and  hold  harmless  Landlord,   its  agents,
contractors (including Building Contractor), and any mortgagee of Landlord, from
and against  any and all losses,  damages,  costs  (including  costs of suit and
attorneys' fees), liabilities, or causes of action for injury to or death of any
person,  for damage to any property,  and for mechanic's  materialmen's or other
liens or  claims  arising  out of or in  connection  with  the work  done by the
Tenant's    contractor   (and   Tenant's    contractor's    subcontractors   and
sub-subcontractors) under its contract with Tenant.

     6. The failure by Tenant,  after receiving  written  notice,  to materially
comply with any of the provisions of Article II of this Exhibit shall constitute
a Default  by Tenant  under the terms of the Lease and  Landlord  shall have the
benefit of all remedies  provided for in the Lease,  except  Tenant shall have a
thirty (30) day right to cure Default upon receipt of written notice .

     7. Upon  completion  of the Tenant  Improvements,  Tenant shall  deliver to
Landlord  two (2)  copies of the "as  built"  plans and  specifications  for the
Tenant  Improvements  completed  under Article II of this Exhibit  within thirty
(30) days of completing the same.


                                       5

                                     - 76 -
<PAGE>

                   EXHIBIT "C" TO A SEVENTH AMENDMENT TO LEASE
                                     BETWEEN
                            LAFP-SF, INC., (LANDLORD)
                                       AND
                 DATA TRANSMISSION NETWORK CORPORATION, (TENANT)
                              DATED JANUARY 5, 1998




                           COMMENCEMENT DATE AGREEMENT


         This Commencement Date Agreement is entered into by Landlord and Tenant
pursuant to Paragraph 1 of this Amendment.

         1.       DEFINITIONS.  In this Agreement the following terms have the
meanings given to them:

                           (a)      Landlord:  LAFP-SF, Inc.

                           (b)      Tenant:  Data Transmission Network
                                    Corporation

                           (c)      Lease:  Lease  between  Landlord and Tenant,
                                    dated May 2, 1995, and subsequently  amended
                                    via  a  First   Amendment   To  Lease  dated
                                    September  29, 1995,  a Second  Amendment To
                                    Lease  dated   January  5,  1996,   a  Third
                                    Amendment To Lease dated  January 5, 1996, a
                                    Fourth Amendment To Lease dated December 23,
                                    1996, a Fifth  Amendment To Lease dated July
                                    7,  1997,  and a Sixth  Amendment  To  Lease
                                    dated July 7, 1997,  a Seventh  Amendment To
                                    Lease  dated  September  19,  1997,  and  an
                                    Eighth  Amendment  To Lease dated  September
                                    19, 1997.

         2.       CONFIRMATION  OF THE  COMMENCEMENT  DATE  WITH  REGARD TO THE
OCCUPANCY,   BY  TENANT,  OF  SUITE.   Landlord  and  Tenant  confirm  that  the
Commencement Date of the Lease with regard to the Expansion  Premises is January
5, 1998.


         Landlord and Tenant have executed this  Commencement  Date Agreement as
of the date set forth above.


Tenant:                                         Landlord:

DATA TRANSMISSION NETWORK                       LAFP-SF, INC.
CORPORATION, a Delaware corporation

                                                By:  Lowe Enterprises Investment
                                                     Management, Inc.
By:                                             Its:  Authorized Agent
   ---------------------------------

Its:                                            By:
    --------------------------------               -----------------------------



                                                Its:
                                                    ----------------------------

                                      6


                                     - 77 -