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                                                                     Exhibit 4.6

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                           American Tower Corporation

                              Warrants to Purchase
                        11,389,012 Shares of Common Stock

                                Warrant Agreement

                          Dated as of January 29, 2003

                              The Bank of New York

                                  Warrant Agent

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               WARRANT AGREEMENT, dated as of January 29, 2003, between American
Tower Corporation, a Delaware corporation (the "Company"), and The Bank of New
York, a New York banking corporation, as warrant agent (the "Warrant Agent").

               WHEREAS, the Company proposes to issue warrants (the "Warrants")
to initially purchase up to an aggregate of 11,389,012 shares of Class A Common
Stock, par value $0.01 per share (the "Common Stock"), of the Company (the
Common Stock issuable on exercise of the Warrants being referred to herein as
the "Warrant Shares"), in connection with the offering (the "Offering") by
American Tower Escrow Corporation ("Escrow Corp."), a Delaware corporation,
which is expected to subsequently merge with and into American Towers, Inc., a
Delaware Corporation ("ATI"), of 808,000 Units (the "Units"), each consisting of
$1,000 principal amount at maturity of Escrow Corp.'s 12.25% Senior Subordinated
Discount Notes due 2008 (the "Notes") and one Warrant, each Warrant initially
representing the right to purchase 14.0953 Warrant Shares at the Exercise Price
(as defined herein). The Notes are to be issued under an indenture (the
"Indenture") among the Company, the Guarantors named therein (from and after the
consummation of the Escrow Corp. Merger (as defined herein)) and The Bank of New
York, as trustee (the "Trustee"), dated the date hereof, on a private placement
basis pursuant to an exemption under Section 4(2) of the United States
Securities Act of 1933, as amended.

               WHEREAS, the Company desires the Warrant Agent to act on behalf
of the Company, and the Warrant Agent is willing so to act in connection with
the issuance of Warrant Certificates (as defined) and other matters as provided
herein.

               NOW, THEREFORE, in consideration of the premises and the mutual
agreements herein set forth, the parties hereto agree as follows:

SECTION 1.     CERTAIN DEFINITIONS.

               As used in this Agreement, the following terms shall have the
following respective meanings:

               "144A Global Warrant" means a global Warrant substantially in the
form of Exhibit A hereto bearing the Global Warrant Legend and the Private
Placement Legend and deposited with or on behalf of, and registered in the name
of, the Depositary or its nominee.

               "Affiliate" of any specified Person means any other Person
directly or indirectly controlling or controlled by or under direct or indirect
common control with such specified Person. For purposes of this definition,
"control," as used with respect to any Person, means the possession, directly or
indirectly, of the power to direct or cause the direction of the management or
policies of such Person, whether through the ownership of voting securities, by
agreement or otherwise; provided that beneficial ownership of 10% or more of the
Voting Stock of a Person will be deemed to be control. No natural person who is
an executive officer or director of a Person shall, solely by virtue of such
position, be deemed to control such Person.

               "Applicable Procedures" means, with respect to any transfer or
exchange of or for beneficial interests in any Global Warrant, the rules and
procedures of the Depositary, Euroclear and Clearstream that apply to such
transfer or exchange.

               "Business Day" means any day other than a Legal Holiday.

               "Clearstream" means Clearstream Banking, S.A.

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               "Closing Date" means the date hereof.

               "Commission" means the Securities and Exchange Commission.

               "Definitive Warrant" means a certificated Warrant registered in
the name of the Holder thereof and issued in accordance with Section 3.5 hereof,
substantially in the form of Exhibit A hereto except that such Warrant shall not
bear the Global Warrant Legend and shall not have the "Schedule of Exchanges of
Interests in the Global Warrant" attached thereto.

               "Depositary" means, with respect to the Warrants issuable or
issued in whole or in part in global form, the Person specified in Section 3.3
hereof as the Depositary with respect to the Warrants, and any and all
successors thereto appointed as Depositary hereunder and having become such
pursuant to the applicable provision of the Indenture.

               "Disinterested Director" means, in connection with any issuance
of securities that gives rise to a determination of the Fair Value thereof, each
member of the Board of Directors of the Company who is not an officer, employee,
director or other affiliate of the party to whom the Company is proposing to
issue the securities giving rise to such determination.

               "Escrow Corp. Merger" means the merger transaction involving
Escrow Corp., a Delaware corporation, and ATI pursuant to the Escrow Corp.
Merger Agreement.

               "Escrow Corp. Merger Agreement" means that certain Agreement and
Plan of Merger dated as of January 29, 2003 by and between Escrow Corp. and ATI
pursuant to which Escrow Corp. is expected to merge with and into ATI.

               "Euroclear" means Euroclear Bank S.A./N.V., as operator of the
Euroclear system.

               "Exchange Act" means the Securities Exchange Act of 1934, as
amended.

               "Exercise Period" has the meaning assigned to it in Section 4(a)
hereof.

               "Exercise Price" means the Initial Exercise Price subject to the
conditions and adjustments described in this Warrant Agreement.

               "Fair Value" per security at any date of determination shall be
(1) in connection with a sale to a party that is not an affiliate of the Company
in an arm's-length transaction (a "Non-Affiliate Sale"), the price per security
at which such security is sold and (2) in connection with any sale to an
affiliate of the Company, (a) the last price per security at which such security
was sold in a Non-Affiliate Sale within the three-month period preceding such
date of determination or (b) if clause (a) is not applicable, the fair market
value of such security determined in good faith by (i) a majority of the Board
of Directors of the Company, including a majority of the disinterested
directors, and approved in a board resolution delivered to the Warrant Agent or
(ii) a nationally recognized investment banking, appraisal or valuation firm,
which is not an affiliate of the Company, in each case taking into account,
among all other factors deemed relevant by the Board of Directors or such
investment banking, appraisal or valuation firm, the trading price and volume of
such security on any national securities exchange or automated quotation system
on which such security is traded.

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               "Global Warrants" means, individually and collectively, each of
the Restricted Global Warrants and the Unrestricted Global Warrants,
substantially in the form of Exhibit A hereto issued in accordance with Section
3.1(b) and 3.5 hereof.

               "Global Warrant Legend" means the legend set forth in Section
3.5(g)(ii), which is required to be placed on all Global Warrants issued under
this Warrant Agreement.

               "Holder" means a person who is listed as the record owner of
Registrable Securities.

               "IAI Global Warrant" means the global Warrant substantially in
the form of Exhibit A hereto bearing the Global Warrant Legend and the Private
Placement Legend and deposited with or on behalf of and registered in the name
of the Depositary or its nominee.

               "Indenture" has the meaning assigned to it in the recitals to
this Agreement.

               "Initial Exercise Price" means $0.01 per Warrant Share.

               "Indirect Participant" means a Person who holds a beneficial
interest in a Global Warrant through a Participant.

               "Initial Purchasers" means Credit Suisse First Boston LLC and
Goldman, Sachs & Co.

               "Institutional Accredited Investor" means an institution that is
an "accredited investor" as defined in Rule 501(a)(1), (2), (3) or (7) under the
Securities Act, which is not also a QIB.

               "Legal Holiday" means a Saturday, a Sunday or a day on which
banking institutions in the City of New York, the City of Boston or the city in
which the principal corporate trust office or the Warrant Agent is located or at
a place of payment are authorized by law, regulation or executive order to
remain closed. If a payment date is a Legal Holiday at a place of payment,
payment may be made at that place on the next succeeding day that is not a Legal
Holiday, and no interest shall accrue on such payment for the intervening
period.

               "Market Value" means the value per share of the Company's Class A
Common Stock, par value $0.01 per share, as of any date, which shall equal (i)
if such Common Stock is primarily traded on a securities exchange, the last sale
price on such securities exchange on the trading day immediately prior to the
date of determination, or if no sale occurred on such day, the mean between the
closing "bid" and "asked" prices on such day, (ii) if the principal market for
such Common Stock is in the over-the-counter market, the closing sale price on
the trading day immediately prior to the date of the determination, as published
by the National Association of Securities Dealers Automated quotation System or
similar organization, or if such price is not so published on such day, the mean
between the closing "bid" and "asked" prices, if available, on such day, which
prices may be obtained from any reputable pricing service, broker or dealer, and
(iii) if neither clause (i) nor clause (ii) is applicable, the fair market value
on the date of determination of such Common Stock as determined in good faith by
the board of directors of the Company.

               "Non-U.S. Person" means a Person who is not a U.S. Person.

               "Notes" has the meaning assigned to it in the recitals to this
Agreement.

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               "Officer" means, with respect to any Person, the Chairman of the
Board, the Chief Executive Officer, the President, the Chief Operating Officer,
the Chief Financial Officer, the Treasurer, any Assistant Treasurer, the
Controller, the Secretary or any Senior or Executive Vice-President of such
Person.

               "Opinion of Counsel" means an opinion from legal counsel. The
counsel may be an employee of or counsel to the Company or any subsidiary of the
Company.

               "Participant" means, with respect to the Depositary, Euroclear or
Clearstream, a Person who has an account with the Depositary, Euroclear or
Clearstream, respectively (and, with respect to The Depository Trust Company,
shall include Euroclear and Clearstream).

               "Person" means any individual, corporation, partnership, joint
venture, association, joint-stock company, trust, unincorporated organization,
limited liability company or government or other entity.

               "Private Placement Legend" means the legend set forth in Section
3.5(g)(i) to be placed on all Warrants issued under this Warrant Agreement
except where otherwise permitted by the provisions of this Warrant Agreement.

               "QIB" means a "qualified institutional buyer" as defined in Rule
144A.

               "Registrable Securities" shall mean the Warrants, the Warrant
Shares and any other securities issued or issuable with respect to the Warrants
or the Warrant Shares by way of a stock dividend or stock split or in connection
with a combination of shares, recapitalization, merger, consolidation or other
reorganization; provided that a security ceases to be a Registrable Security
when it is no longer a Transfer Restricted Security. The Registrable Securities
are entitled to the benefits of the Warrant Registration Rights Agreement.

               "Registration Statement" means the Registration Statement as
defined in the Warrant Registration Rights Agreement.

               "Regulation S" means Regulation S promulgated under the
Securities Act.

               "Regulation S Global Warrant" means a global Warrant in the form
of Exhibit A hereto bearing the Global Warrant Legend, the Private Placement
Legend and the Regulation S Legend and deposited with or on behalf of and
registered in the name of the Depositary or its nominee.

               "Regulation S Legend" means the legend set forth in Section
3.5(g)(iv) to be placed on all Registrable Securities issued pursuant to
Regulation S.

               "Restricted Definitive Warrant" means a Definitive Warrant
bearing the Private Placement Legend.

               "Restricted Global Warrant" means a Global Warrant bearing the
Private Placement Legend.

               "Restricted Period" means the one-year distribution compliance
period as defined in Regulation S.

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               "Rule 144" means Rule 144 promulgated under the Securities Act.

               "Rule 144A" means Rule 144A promulgated under the Securities Act.

               "Rule 903" means Rule 903 promulgated under the Securities Act.

               "Rule 904" means Rule 904 promulgated under the Securities Act.

               "Securities Act" means the Securities Act of 1933, as amended.

               "Separation Date" means the earliest to occur of (i) 180 days
after the closing of the Offering, (ii) the date on which a registration
statement with respect to a registered exchange offer for the Notes is declared
effective under the Securities Act, (iii) the date a shelf registration
statement with respect to the Warrants is declared effective under the
Securities Act, (iv) such date as Credit Suisse First Boston LLC in its sole
discretion shall determine and (v) in the event of Change of Control (as defined
in the Indenture), the date the Company mails the requisite notice to the
holders.

               "Transfer Agent" shall have the meaning assigned to it in Section
6(b) hereof.

               "Transfer Restricted Securities" means (a) each Warrant and
Warrant Share held by an Affiliate of the Company and (b) each other Warrant and
Warrant Share until the earlier to occur of (i) the date on which such Warrant
or Warrant Share (other than any Warrant Share issued upon exercise of a Warrant
in accordance with a Registration Statement (as defined in the Warrant
Registration Rights Agreement) has been disposed of in accordance with a
Registration Statement and (ii) the date on which such Warrant or Warrant Share
(or the related Warrant) is distributed to the public pursuant to Rule 144 under
the Act.

               "Trustee" has the meaning assigned to it in the recitals to this
Agreement.

               "Unrestricted Global Warrant" means a global Warrant
substantially in the form of Exhibit A attached hereto that bears the Global
Warrant Legend and that has the "Schedule of Exchanges of Interests in the
Global Warrant" attached thereto, and that is deposited with or on behalf of and
registered in the name of the Depositary, representing a series of Warrants that
do not bear the Private Placement Legend.

               "Unrestricted Definitive Warrant" means one or more Definitive
Warrants that do not bear and are not required to bear the Private Placement
Legend.

               "U.S. Person" means a U.S. person as defined in Rule 902(o) under
the Securities Act.

               "Warrants" has the meaning assigned to it in the recitals to this
Agreement.

               "Warrant Certificates" shall have the meaning assigned to it in
Section 3.1(a) hereof.

               "Warrant Registration Rights Agreement" means the registration
rights agreement, dated as of January 29, 2003, between the Company and the
Initial Purchasers relating to the Warrants and the Warrant Shares.

               "Warrant Shares" has the meaning assigned to it in the recitals
to this Agreement.

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SECTION 2.     APPOINTMENT OF WARRANT AGENT.

               The Company hereby appoints the Warrant Agent to act as agent for
the Company in accordance with the instructions set forth hereinafter in this
Agreement and the Warrant Agent hereby accepts such appointment.

SECTION 3.     ISSUANCE OF WARRANTS; WARRANT CERTIFICATES.

        3.1.   FORM AND DATING.

               (a)  General.

               The Warrants shall be substantially in the form of Exhibit A
hereto (the "Warrant Certificates"). The Warrants may have notations, legends or
endorsements required by law, stock exchange rule or usage. Each Warrant shall
be dated the date of the countersignature.

               The terms and provisions contained in the Warrants shall
constitute, and are hereby expressly made, a part of this Warrant Agreement. The
Company and the Warrant Agent, by their execution and delivery of this Warrant
Agreement, expressly agree to such terms and provisions and to be bound thereby.
However, to the extent any provision of any Warrant conflicts with the express
provisions of this Warrant Agreement, the provisions of this Warrant Agreement
shall govern and be controlling.

               (b)  Global Warrants.

               Warrants issued in global form shall be substantially in the form
of Exhibit A attached hereto (including the Global Warrant Legend thereon and
the "Schedule of Exchanges of Interests in the Global Warrant" attached
thereto). Warrants issued in definitive form shall be substantially in the form
of Exhibit A attached hereto (but without the Global Warrant Legend thereon and
without the "Schedule of Exchanges of Interests in the Global Warrant" attached
thereto). Each Global Warrant shall represent such of the outstanding Warrants
as shall be specified therein and each shall provide that it shall represent the
number of outstanding Warrants from time to time endorsed thereon and that the
number of outstanding Warrants represented thereby may from time to time be
reduced or increased, as appropriate, to reflect exchanges and redemptions. Any
endorsement of a Global Warrant to reflect the amount of any increase or
decrease in the number of outstanding Warrants represented thereby shall be made
by the Warrant Agent in accordance with instructions given by the Holder thereof
as required by Section 3.5 hereof.

               (c)  Euroclear and Clearstream Procedures Applicable.

               The provisions of the "Operating Procedures of the Euroclear
System" and "Terms and Conditions Governing Use of Euroclear" and the "General
Terms and Conditions of Clearstream Banking" and "Customer Handbook" of
Clearstream will be applicable to transfers of beneficial interests in the
Regulation S Global Warrants that are held by Participants through Euroclear or
Clearsteam.

        3.2.   EXECUTION.

               An Officer shall sign the Warrants for the Company by manual or
facsimile signature.

               If the Officer whose signature is on a Warrant no longer holds
that office at the time a Warrant is countersigned, the Warrant shall
nevertheless be valid.

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               A Warrant shall not be valid until countersigned by the manual
signature of the Warrant Agent. The signature (which may be a facsimile) shall
be conclusive evidence that the Warrant has been properly issued under this
Warrant Agreement.

               The Warrant Agent shall, upon a written order of the Company
signed by an Officer (a "Warrant Countersignature Order"), countersign Warrants
for original issue up to the number stated in the preamble hereto.

               The Warrant Agent may appoint an agent acceptable to the Company
to countersign Warrants. Such an agent may countersign Warrants whenever the
Warrant Agent may do so. Each reference in this Warrant Agreement to a
countersignature by the Warrant Agent includes a countersignature by such agent.
Such an agent has the same rights as the Warrant Agent to deal with Holders, the
Company or an Affiliate of the Company.

        3.3.   WARRANT REGISTRAR.

               The Company shall maintain an office or agency where Warrants may
be presented for registration of transfer or for exchange ("Warrant Registrar").
The Warrant Registrar shall keep a register of the Warrants and of their
transfer and exchange. The Company may appoint one or more co-Warrant
Registrars. The term "Warrant Registrar" includes any co-Warrant Registrar. The
Company may change any Warrant Registrar without notice to any holder. The
Company shall notify the Warrant Agent in writing of the name and address of any
agent not a party to this Warrant Agreement. If the Company fails to appoint or
maintain another entity as Warrant Registrar, the Warrant Agent shall act as
such. The Company or any of its subsidiaries may act as Warrant Registrar.

               The Company initially appoints The Depository Trust Company
("DTC") to act as Depositary with respect to the Global Warrants.

               The Company initially appoints the Warrant Agent to act as the
Warrant Registrar with respect to the Global Warrants.

        3.4.   HOLDER LISTS.

               The Warrant Agent shall preserve in as current a form as is
reasonably practicable the most recent list available to it of the names and
addresses of all Holders. If the Warrant Agent is not the Warrant Registrar, the
Company shall promptly furnish to the Warrant Agent at such times as the Warrant
Agent may request in writing, a list in such form and as of such date as the
Warrant Agent may reasonably require of the names and addresses of the Holders.

        3.5.   TRANSFER AND EXCHANGE.

        (a)    Transfer and Exchange of Global Warrants.

               A Global Warrant may not be transferred as a whole except by the
Depositary to a nominee of the Depositary, by a nominee of the Depositary to the
Depositary or to another nominee of the Depositary, or by the Depositary or any
such nominee to a successor Depositary or a nominee of such successor
Depositary. All Global Warrants will be exchanged by the Company for Definitive
Warrants if (i) the Company delivers to the Warrant Agent notice from the
Depositary that it is unwilling or unable to continue to act as Depositary or
that it is no longer a clearing agency registered under the Exchange Act and, in
either case, a successor Depositary is not appointed by the Company within 120
days after the date

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of such notice from the Depositary; (ii) in the case of a Global Warrant held
for an account of Euroclear or Clearstream, Euroclear or Clearstream, as the
case may be, (a) is closed for business for a continuous period of 14 days
(other than by reason of statutory or other holidays), or (b) announces an
intention permanently to cease business or does in fact do so; or (iii) the
Company in its sole discretion determines that the Global Warrants (in whole but
not in part) should be exchanged for Definitive Warrants and delivers a written
notice to such effect to the Warrant Agent. Upon the occurrence of any of the
preceding events in (i), (ii) or (iii) above, Definitive Warrants shall be
issued in such names as the Depositary shall instruct the Warrant Agent. Global
Warrants also may be exchanged or replaced, in whole or in part, as provided in
Sections 3.6 and 3.7 hereof. A Global Warrant may not be exchanged for another
Warrant other than as provided in this Section 3.5(a), however, beneficial
interests in a Global Warrant may be transferred and exchanged as provided in
Section 3.5(b), (c) or (f) hereof.

        (b)    Transfer and Exchange of Beneficial Interests in the Global
               Warrants.

               The transfer and exchange of beneficial interests in the Global
Warrants shall be effected through the Depositary, in accordance with the
provisions of this Warrant Agreement and the Applicable Procedures. Beneficial
interests in the Restricted Global Warrants shall be subject to restrictions on
transfer comparable to those set forth herein to the extent required by the
Securities Act. Transfers of beneficial interests in the Global Warrants also
shall require compliance with either subparagraph (i) or (ii) below, as
applicable, as well as one or more of the other following subparagraphs, as
applicable:

               (i) Transfer of Beneficial Interests in the Same Global Warrant.
        Beneficial interests in any Restricted Global Warrant may be transferred
        to Persons who take delivery thereof in the form of a beneficial
        interest in the same Restricted Global Warrant in accordance with the
        transfer restrictions set forth in the Private Placement Legend;
        provided, however, that prior to the expiration of the Restricted
        Period, transfers of beneficial interests in the Regulation S Global
        Warrant may not be made to a U.S. Person or for the account or benefit
        of a U.S. Person (other than the Initial Purchaser). Beneficial
        interests in any Unrestricted Global Warrant may be transferred to
        Persons who take delivery thereof in the form of a beneficial interest
        in an Unrestricted Global Warrant. No written orders or instructions
        shall be required to be delivered to the Warrant Registrar to effect the
        transfers described in this Section 3.5(b)(i).

               (ii) All Other Transfers and Exchanges of Beneficial Interests in
        Global Warrants. In connection with all transfers and exchanges of
        beneficial interests that are not subject to Section 3.5(b)(i) above,
        the transferor of such beneficial interest must deliver to the Warrant
        Registrar either (A) both (1) a written order from a Participant or an
        Indirect Participant given to the Depositary in accordance with the
        Applicable Procedures directing the Depositary to credit or cause to be
        credited a beneficial interest in another Global Warrant in an amount
        equal to the beneficial interest to be transferred or exchanged and (2)
        instructions given in accordance with the Applicable Procedures
        containing information regarding the Participant account to be credited
        with such increase or (B) both (1) a written order from a Participant or
        an Indirect Participant given to the Depositary in accordance with the
        Applicable Procedures directing the Depositary to cause to be issued a
        Definitive Warrant in an amount equal to the beneficial interest to be
        transferred or exchanged and (2) instructions given by the Depositary to
        the Warrant Registrar containing information regarding the Person in
        whose name such Definitive Warrant shall be registered to effect the
        transfer or exchange referred to in (1) above. Upon effectiveness of the
        Registration Statement (as defined in the Warrant Registration Rights
        Agreement) by the Company in accordance with Section 3.5(f) hereof, the
        requirements of this Section 3.5(b)(ii) shall be deemed to have been
        satisfied upon receipt by the Warrant Registrar of a certification
        required by the Company in connection with such Registration Statement
        delivered by the Holder

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        of such beneficial interests in the Restricted Global Warrants. Upon
        satisfaction of all of the requirements for transfer or exchange of
        beneficial interests in Global Warrants contained in this Agreement and
        the Warrants or otherwise applicable under the Securities Act, the
        Warrant Agent shall adjust the principal amount of the relevant Global
        Warrant(s) pursuant to Section 3.5(h) hereof.

               (iii) Transfer of Beneficial Interests to Another Restricted
        Global Warrant. A beneficial interest in any Restricted Global Warrant
        may be transferred to a Person who takes delivery thereof in the form of
        a beneficial interest in another Restricted Global Warrant if the
        transfer complies with the requirements of Section 3.5(b)(ii) above and
        the Warrant Registrar receives the following:

                    (A) if the transferee will take delivery in the form of a
               beneficial interest in the 144A Global Warrant, then the
               transferor must deliver a certificate in the form of Exhibit B
               hereto, including the certifications in item (1) thereof;

                    (B) if the transferee will take delivery in the form of a
               beneficial interest in the Regulation S Global Warrant, then the
               transferor must deliver a certificate in the form of Exhibit B
               hereto, including the certifications in item (2) thereof; and

                    (C) if the transferee will take delivery in the form of a
               beneficial interest in the IAI Global Warrant, then the
               transferor must deliver a certificate in the form of Exhibit B
               hereto, including the certifications and certificates and Opinion
               of Counsel required by item (3) thereof, if applicable.

               (iv) Transfer and Exchange of Beneficial Interests in a
        Restricted Global Warrant for Beneficial Interests in the Unrestricted
        Global Warrant. A beneficial interest in any Restricted Global Warrant
        may be exchanged by any holder thereof for a beneficial interest in an
        Unrestricted Global Warrant or transferred to a Person who takes
        delivery thereof in the form of a beneficial interest in an Unrestricted
        Global Warrant if the exchange or transfer complies with the
        requirements of Section 3.5(b)(ii) above and:

                    (A) such transfer is effected pursuant to the Registration
               Statement in accordance with the Warrant Registration Rights
               Agreement; or

                    (B) the Warrant Registrar receives the following:

                         (1) if the holder of such beneficial interest in a
                    Restricted Global Warrant proposes to exchange such
                    beneficial interest for a beneficial interest in an
                    Unrestricted Global Warrant, a certificate from such holder
                    in the form of Exhibit C hereto, including the
                    certifications in item (1)(a) thereof; or

                         (2) if the holder of such beneficial interest in a
                    Restricted Global Warrant proposes to transfer such
                    beneficial interest to a Person who shall take delivery
                    thereof in the form of a beneficial interest in an
                    Unrestricted Global Warrant, a certificate from such holder
                    in the form of Exhibit B hereto, including the
                    certifications in item (4) thereof;

        and, in each such case set forth in this subparagraph (B), if the
        Warrant Registrar so requests or if the Applicable Procedures so
        require, an Opinion of Counsel in form reasonably acceptable to the

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        Warrant Registrar to the effect that such exchange or transfer is in
        compliance with the Securities Act and that the restrictions on transfer
        contained herein and in the Private Placement Legend are no longer
        required in order to maintain compliance with the Securities Act.

               If any such transfer is effected pursuant to subparagraph (B)
above at a time when an Unrestricted Global Warrant has not yet been issued, the
Company shall issue and, upon receipt of an Warrant Countersignature Order in
accordance with Section 3.2 hereof, the Warrant Agent shall countersign one or
more Unrestricted Global Warrants in the number equal to the number of
beneficial interests transferred pursuant to subparagraph (B) above.

               Beneficial interests in an Unrestricted Global Warrant cannot be
exchanged for, or transferred to Persons who take delivery thereof in the form
of, a beneficial interest in a Restricted Global Warrant.

        (c)    Transfer and Exchange of Beneficial Interests for Definitive
               Warrants.

               (i)  Beneficial Interests in Restricted Global Warrants to
        Restricted Definitive Warrants. If any holder of a beneficial interest
        in a Restricted Global Warrant proposes to exchange such beneficial
        interest for a Restricted Definitive Warrant or to transfer such
        beneficial interest to a Person who takes delivery thereof in the form
        of a Restricted Definitive Warrant, then, upon receipt by the Warrant
        Registrar of the following documentation:

                    (A) if the holder of such beneficial interest in a
               Restricted Global Warrant proposes to exchange such beneficial
               interest for a Restricted Definitive Warrant, a certificate from
               such holder in the form of Exhibit C hereto, including the
               certifications in item (2)(a) thereof;

                    (B) if such beneficial interest is being transferred to a
               QIB in accordance with Rule 144A, a certificate to the effect set
               forth in Exhibit B hereto, including the certifications in item
               (1) thereof;

                    (C) if such beneficial interest is being transferred to a
               Non-U.S. Person in an offshore transaction in accordance with
               Rule 903 or Rule 904 under the Securities Act, a certificate to
               the effect set forth in Exhibit B hereto, including the
               certifications in item (2) thereof;

                    (D) if such beneficial interest is being transferred
               pursuant to an exemption from the registration requirements of
               the Securities Act in accordance with Rule 144, a certificate to
               the effect set forth in Exhibit B hereto, including the
               certifications in item (3)(a) thereof;

                    (E) if such beneficial interest is being transferred to an
               Institutional Accredited Investor in reliance on an exemption
               from the registration requirements of the Securities Act other
               than those listed in subparagraphs (B) through (D) above, a
               certificate to the effect set forth in Exhibit B hereto,
               including the certifications, certificates and Opinion of Counsel
               required by item (3) thereof, if applicable;

                    (F) if such beneficial interest is being transferred to the
               Company or any of its Subsidiaries, a certificate to the effect
               set forth in Exhibit B hereto, including the certifications in
               item (3)(b) thereof; or

                                       10

<PAGE>

                    (G) if such beneficial interest is being transferred
               pursuant to an effective registration statement under the
               Securities Act, a certificate to the effect set forth in Exhibit
               B hereto, including the certifications in item (3)(c) thereof,

the Warrant Agent shall cause, in accordance with the standing instructions and
procedures existing between the Depositary and the Warrant Agent, the number of
Warrants represented by the Global Warrant to be reduced by the number of
Warrants to be represented by the Definitive Warrant pursuant to Section 3.5(h)
hereof, and the Company shall execute and the Warrant Agent shall countersign
and deliver to the Person designated in the instructions a Definitive Warrant in
the appropriate amount. Any Definitive Warrant issued in exchange for a
beneficial interest in a Restricted Global Warrant pursuant to this Section
3.5(c) shall be registered in such name or names as the holder of such
beneficial interest shall instruct the Warrant Registrar through instructions
from the Depositary and the Participant or Indirect Participant. The Warrant
Agent shall deliver such Definitive Warrants to the Persons in whose names such
Warrants are so registered. Any Definitive Warrant issued in exchange for a
beneficial interest in a Restricted Global Warrant pursuant to this Section
3.5(c)(i) shall bear the Private Placement Legend and shall be subject to all
restrictions on transfer contained therein.

               (ii) Beneficial Interests in Restricted Global Warrants to
        Unrestricted Definitive Warrants. A holder of a beneficial interest in a
        Restricted Global Warrant may exchange such beneficial interest for an
        Unrestricted Definitive Warrant or may transfer such beneficial interest
        to a Person who takes delivery thereof in the form of an Unrestricted
        Definitive Warrant only if:

                    (A) such transfer is effected pursuant to the Registration
               Statement in accordance with the Warrant Registration Rights
               Agreement; or

                    (B) the Warrant Registrar receives the following:

                        (1) if the holder of such beneficial interest in a
                    Restricted Global Warrant proposes to exchange such
                    beneficial interest for a Definitive Warrant that does not
                    bear the Private Placement Legend, a certificate from such
                    holder in the form of Exhibit C hereto, including the
                    certifications in item (1)(b) thereof; or

                        (2) if the holder of such beneficial interest in a
                    Restricted Global Warrant proposes to transfer such
                    beneficial interest to a Person who shall take delivery
                    thereof in the form of a Definitive Warrant that does not
                    bear the Private Placement Legend, a certificate from such
                    holder in the form of Exhibit B hereto, including the
                    certifications in item (4) thereof;

               and, in each such case set forth in this subparagraph (B), if the
               Warrant Registrar so requests or if the Applicable Procedures so
               require, an Opinion of Counsel in form reasonably acceptable to
               the Warrant Registrar to the effect that such exchange or
               transfer is in compliance with the Securities Act and that the
               restrictions on transfer contained herein and in the Private
               Placement Legend are no longer required in order to maintain
               compliance with the Securities Act.

               (iii) Beneficial Interests in Unrestricted Global Warrants to
        Unrestricted Definitive Warrants. If any holder of a beneficial interest
        in an Unrestricted Global Warrant proposes to exchange such beneficial
        interest for a Definitive Warrant or to transfer such beneficial
        interest to a Person who takes delivery thereof in the form of a
        Definitive Warrant, then, upon satisfaction of the conditions set forth
        in Section 3.5(b)(ii) hereof, the Warrant Agent shall cause the amount
        of

                                       11

<PAGE>

        the applicable Global Warrant to be reduced accordingly pursuant to
        Section 3.5(h) hereof, and the Company shall execute and the Warrant
        Agent shall countersign and deliver to the Person designated in the
        instructions a Definitive Warrant in the appropriate principal amount.
        Any Definitive Warrant issued in exchange for a beneficial interest
        pursuant to this Section 3.5(c)(iii) shall be registered in such name or
        names and in such authorized denomination or denominations as the holder
        of such beneficial interest shall instruct the Warrant Registrar through
        instructions from the Depositary and the Participant or Indirect
        Participant. The Warrant Agent shall deliver such Definitive Warrants to
        the Persons in whose names such Warrants are so registered. Any
        Definitive Warrant issued in exchange for a beneficial interest pursuant
        to this Section 3.5(c)(iii) shall not bear the Private Placement Legend.

        (d)    Transfer and Exchange of Definitive Warrants for Beneficial
               Interests.

               (i)  Restricted Definitive Warrants to Beneficial Interests in
        Restricted Global Warrants. If any Holder of a Restricted Definitive
        Warrant proposes to exchange such Warrant for a beneficial interest in a
        Restricted Global Warrant or to transfer such Restricted Definitive
        Warrants to a Person who takes delivery thereof in the form of a
        beneficial interest in a Restricted Global Warrant, then, upon receipt
        by the Warrant Registrar of the following documentation:

                    (A) if the Holder of such Restricted Definitive Warrant
               proposes to exchange such Warrant for a beneficial interest in a
               Restricted Global Warrant, a certificate from such Holder in the
               form of Exhibit C hereto, including the certifications in item
               (2)(b) thereof;

                    (B) if such Restricted Definitive Warrant is being
               transferred to a QIB in accordance with Rule 144A under the
               Securities Act, a certificate to the effect set forth in Exhibit
               B hereto, including the certifications in item (1) thereof;

                    (C) if such Restricted Definitive Warrant is being
               transferred to a Non-U.S. Person in an offshore transaction in
               accordance with Rule 903 or Rule 904 under the Securities Act, a
               certificate to the effect set forth in Exhibit B hereto,
               including the certifications in item (2) thereof;

                    (D) if such Restricted Definitive Warrant is being
               transferred pursuant to an exemption from the registration
               requirements of the Securities Act in accordance with Rule 144
               under the Securities Act, a certificate to the effect set forth
               in Exhibit B hereto, including the certifications in item (3)(a)
               thereof

                    (E) if such Restricted Definitive Warrant is being
               transferred to an Institutional Accredited Investor in reliance
               on an exemption from the registration requirements of the
               Securities Act other than those listed in subparagraphs (B)
               through (D) above, a certificate to the effect set forth in
               Exhibit B hereto, including the certifications, certificates and
               Opinion of Counsel required by item (3) thereof, if applicable;

                    (F) if such Restricted Definitive Warrant is being
               transferred to the Company or any of its Subsidiaries, a
               certificate to the effect set forth in Exhibit B hereto,
               including the certifications in item (3)(b) thereof; or

                                       12

<PAGE>

                    (G) if such Restricted Definitive Warrant is being
               transferred pursuant to an effective registration statement under
               the Securities Act, a certificate to the effect set forth in
               Exhibit B hereto, including the certifications in item (3)(c)
               thereof,

        the Warrant Agent shall cancel the Restricted Definitive Warrant,
        increase or cause to be increased the amount of, in the case of clause
        (A) above, the appropriate Restricted Global Warrant, in the case of
        clause (B) above, the 144A Global Warrant, in the case of clause (C)
        above, the Regulation S Global Warrant, and in all other cases, the IAI
        Global Warrant.

               (ii) Restricted Definitive Warrants to Beneficial Interests in
        Unrestricted Global Warrants. A Holder of a Restricted Definitive
        Warrant may exchange such Warrant for a beneficial interest in an
        Unrestricted Global Warrant or transfer such Restricted Definitive
        Warrant to a Person who takes delivery thereof in the form of a
        beneficial interest in an Unrestricted Global Warrant only if:

                    (A) such transfer is effected pursuant to the Registration
               Statement in accordance with the Registration Rights Agreement;
               or

                    (B) the Warrant Registrar receives the following:

                        (1) if the Holder of such Definitive Warrants proposes
                    to exchange such Warrants for a beneficial interest in the
                    Unrestricted Global Warrant, a certificate from such Holder
                    in the form of Exhibit C hereto, including the
                    certifications in item (1)(c) thereof; or

                        (2) if the Holder of such Definitive Warrants proposes
                    to transfer such Warrants to a Person who shall take
                    delivery thereof in the form of a beneficial interest in the
                    Unrestricted Global Warrant, a certificate from such Holder
                    in the form of Exhibit B hereto, including the
                    certifications in item (4) thereof;

               and, in each such case set forth in this subparagraph (B), if the
               Warrant Registrar so requests or if the Applicable Procedures so
               require, an Opinion of Counsel in form reasonably acceptable to
               the Warrant Registrar to the effect that such exchange or
               transfer is in compliance with the Securities Act and that the
               restrictions on transfer contained herein and in the Private
               Placement Legend are no longer required in order to maintain
               compliance with the Securities Act.

               Upon satisfaction of the conditions of any of the subparagraphs
        in this Section 3.5(d)(ii), the Warrant Agent shall cancel the
        Definitive Warrants and increase or cause to be increased the aggregate
        principal amount of the Unrestricted Global Warrant.

               (iii) Unrestricted Definitive Warrants to Beneficial Interests in
        Unrestricted Global Warrants. A Holder of an Unrestricted Definitive
        Warrant may exchange such Warrant for a beneficial interest in an
        Unrestricted Global Warrant or transfer such Definitive Warrants to a
        Person who takes delivery thereof in the form of a beneficial interest
        in an Unrestricted Global Warrant at any time. Upon receipt of a request
        for such an exchange or transfer, the Warrant Agent shall cancel the
        applicable Unrestricted Definitive Warrant and increase or cause to be
        increased the amount of one of the Unrestricted Global Warrants.

                                       13

<PAGE>

               If any such exchange or transfer from a Definitive Warrant to a
        beneficial interest is effected pursuant to subparagraphs (ii)(B) or
        (iii) above at a time when an Unrestricted Global Warrant has not yet
        been issued, the Company shall issue and, upon receipt of an Warrant
        Countersignature Order in accordance with Section 3.2 hereof, the
        Warrant Agent shall countersign one or more Unrestricted Global Warrants
        in the number equal to the number of beneficial interests of Definitive
        Warrants so transferred.

        (e)    Transfer and Exchange of Definitive Warrants for Definitive
               Warrants.

               Upon request by a Holder of Definitive Warrants and such Holder's
compliance with the provisions of this Section 3.5(e), the Warrant Registrar
shall register the transfer or exchange of Definitive Warrants. Prior to such
registration of transfer or exchange, the requesting Holder shall present or
surrender to the Warrant Registrar the Definitive Warrants duly endorsed or
accompanied by a written instruction of transfer in form satisfactory to the
Warrant Registrar duly executed by such Holder or by its attorney, duly
authorized in writing. In addition, the requesting Holder shall provide any
additional certifications, documents and information, as applicable, required
pursuant to the following provisions of this Section 3.5(e).

               (i)  Restricted Definitive Warrants to Restricted Definitive
               Warrants. Any Restricted Definitive Warrant may be transferred to
               and registered in the name of Persons who take delivery thereof
               in the form of a Restricted Definitive Warrant if the Warrant
               Registrar receives the following:

                    (A) if the transfer will be made pursuant to Rule 144A under
               the Securities Act, then the transferor must deliver a
               certificate in the form of Exhibit B hereto, including the
               certifications in item (1) thereof;

                    (B) if the transfer will be made pursuant to Rule 903 or
               Rule 904, then the transferor must deliver a certificate in the
               form of Exhibit B hereto, including the certifications in item
               (2) thereof; or

                    (C) if the transfer will be made pursuant to any other
               exemption from the registration requirements of the Securities
               Act, then the transferor must deliver a certificate in the form
               of Exhibit B hereto, including the certifications, certificates
               and Opinion of Counsel required by item (3) thereof, if
               applicable.

               (ii) Restricted Definitive Warrants to Unrestricted Definitive
          Warrants. Any Restricted Definitive Warrant may be exchanged by the
          Holder thereof for an Unrestricted Definitive Warrant or transferred
          to a Person or Persons who take delivery thereof in the form of an
          Unrestricted Definitive Warrant if:

                    (A) any such transfer is effected pursuant to the
               Registration Statement in accordance with the Warrant
               Registration Rights Agreement; or

                    (B) the Warrant Registrar receives the following:

                        (1) if the Holder of such Restricted Definitive
                    Warrants proposes to exchange such Warrants for an
                    Unrestricted Definitive Warrant, a certificate from such
                    Holder in the form of Exhibit C hereto, including the
                    certifications in item (1)(d) thereof; or

                                       14

<PAGE>

                        (2) if the Holder of such Restricted Definitive
                    Warrants proposes to transfer such Warrants to a Person who
                    shall take delivery thereof in the form of an Unrestricted
                    Definitive Warrant, a certificate from such Holder in the
                    form of Exhibit B hereto, including the certifications in
                    item (4) thereof;

               and, in each such case set forth in this subparagraph (B), if the
               Warrant Registrar so requests, an Opinion of Counsel in form
               reasonably acceptable to the Company to the effect that such
               exchange or transfer is in compliance with the Securities Act and
               that the restrictions on transfer contained herein and in the
               Private Placement Legend are no longer required in order to
               maintain compliance with the Securities Act.

               (iii) Unrestricted Definitive Warrants to Unrestricted Definitive
        Warrants. A Holder of Unrestricted Definitive Warrants may transfer such
        Warrants to a Person who takes delivery thereof in the form of an
        Unrestricted Definitive Warrant. Upon receipt of a request to register
        such a transfer, the Warrant Registrar shall register the Unrestricted
        Definitive Warrants pursuant to the instructions from the Holder
        thereof.

        (f)    Registration Statement.

               Upon the effectiveness of the Registration Statement and sales of
Warrants in connection therewith in accordance with the Warrant Registration
Rights Agreement, the Company shall issue and, upon receipt of a Warrant
Countersignature Order in accordance with Section 3.2, the Warrant Agent shall
countersign (i) one or more Unrestricted Global Warrants in an amount equal to
the amount of the beneficial interests in the Restricted Global Warrants sold
under such Registration Statement and (ii) Unrestricted Definitive Warrants in
an amount equal to the amount of the beneficial interests of the Restricted
Definitive Warrants sold under such Registration Statement. Concurrently with
the issuance of such Warrants, the Warrant Agent shall cause the amount of the
applicable Restricted Global Warrants to be reduced accordingly, and the Company
shall execute and the Warrant Agent shall countersign and deliver to the Persons
designated by the Holders of Definitive Warrants so accepted Unrestricted
Definitive Warrants in the appropriate amount.

        (g)    Legends.

               The following legends shall appear on the face of all Global
Warrants and Definitive Warrants issued under this Warrant Agreement unless
specifically stated otherwise in the applicable provisions of this Warrant
Agreement.

               (i)  Private Placement Legend.

                    (C) Except as permitted by subparagraph (B) below, each
               Global Warrant and each Definitive Warrant (and all Warrants
               issued in exchange therefor or substitution thereof) shall bear
               the legend in substantially the following form unless otherwise
               agreed by the Company and the holder thereof:

               "THIS SECURITY (OR ITS PREDECESSOR) AND THE WARRANT SHARES TO BE
        ISSUED UPON ITS EXERCISE WAS ORIGINALLY ISSUED IN A TRANSACTION EXEMPT
        FROM REGISTRATION UNDER THE UNITED STATES SECURITIES ACT OF 1933 (THE
        "SECURITIES ACT"). ACCORDINGLY, THIS SECURITY MAY NOT BE OFFERED, SOLD
        OR OTHERWISE TRANSFERRED IN THE ABSENCE OF SUCH REGISTRATION OR AN
        APPLICABLE EXEMPTION THEREFROM. EACH PURCHASER

                                       15

<PAGE>

        OF THIS SECURITY IS HEREBY NOTIFIED THAT THE SELLER OF THIS SECURITY MAY
        BE RELYING ON THE EXEMPTION FROM THE PROVISIONS OF SECTION 5 OF THE
        SECURITIES ACT PROVIDED BY RULE 144A THEREUNDER.

               THE HOLDER OF THIS SECURITY AGREES FOR THE BENEFIT OF THE COMPANY
        THAT (A) THIS SECURITY MAY BE OFFERED, RESOLD, PLEDGED OR OTHERWISE
        TRANSFERRED, ONLY (I) IN THE UNITED STATES TO A PERSONWHOM THE SELLER
        REASONABLY BELIEVES IS A QUALIFIED INSTITUTIONAL BUYER (AS DEFINED IN
        RULE 144A UNDER THE SECURITIES ACT) IN A TRANSACTION MEETING THE
        REQUIREMENTS OF RULE 144A, (II) OUTSIDE THE UNITED STATES IN AN OFFSHORE
        TRANSACTION IN ACCORDANCE WITH RULE 904 UNDER THE SECURITIES ACT, (III)
        PURSUANT TO AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT
        PROVIDED BY RULE 144 THEREUNDER (IF AVAILABLE) OR (IV) PURSUANT TO AN
        EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT, IN EACH OF
        CASES (I) THROUGH (IV) IN ACCORDANCE WITH ANY APPLICABLE SECURITIES LAWS
        OF ANY STATE OF THE UNITED STATES, AND (B) THE HOLDERWILL, AND EACH
        SUBSEQUENT HOLDER IS REQUIRED TO, NOTIFY ANY PURCHASER OF THIS NOTE FROM
        IT OF THE RESALE RESTRICTIONS REFERRED TO IN (A) ABOVE.

               THE HOLDER OF THIS SECURITY AGREES NOT TO ENGAGE IN HEDGING
        TRANSACTIONS UNLESS IN COMPLIANCE WITH THE SECURITIES ACT AND (4) AGREES
        THAT IT WILL DELIVER TO EACH PERSON TO WHOM THIS SECURITY OR AN INTEREST
        HEREIN IS TRANSFERRED A NOTICE SUBSTANTIALLY TO THE EFFECT OF THIS
        LEGEND.

               AS USED HEREIN, THE TERMS "OFFSHORE TRANSACTION" AND "UNITED
        STATES" HAVE THE MEANINGS GIVEN TO THEM BY RULE 902 OF REGULATION S
        UNDER THE SECURITIES ACT. THE WARRANT AGREEMENT CONTAINS A PROVISION
        REQUIRING THE WARRANT AGENT TO REFUSE TO REGISTER ANY TRANSFER OF THIS
        SECURITY IN VIOLATION OF THE FOREGOING."

                    (B) Notwithstanding the foregoing, any Global Warrant or
               Definitive Warrant issued pursuant to subparagraphs (b)(iv),
               (c)(ii), (c)(iii), (d)(ii), (d)(iii), (e)(ii), (e)(iii) or (f) to
               this Section 3.5 (and all Warrants issued in exchange therefor or
               substitution thereof) shall not bear the Private Placement
               Legend.

               (ii) Global Warrant Legend. Each Global Warrant shall bear a
        legend in substantially the following form unless otherwise agreed by
        the Company and the holder thereof:

               "THIS GLOBAL WARRANT IS HELD BY THE DEPOSITARY (AS DEFINED IN THE
        WARRANT AGREEMENT GOVERNING THIS WARRANT) OR ITS NOMINEE IN CUSTODY FOR
        THE BENEFIT OF THE BENEFICIAL OWNERS HEREOF, AND IS NOT TRANSFERABLE TO
        ANY PERSON UNDER ANY CIRCUMSTANCES EXCEPT THAT (I) THE WARRANT AGENT MAY
        MAKE SUCH NOTATIONS HEREON AS MAY BE REQUIRED PURSUANT TO SECTION 3.5 OF
        THE WARRANT AGREEMENT, (II) THIS GLOBAL WARRANT MAY BE EXCHANGED IN
        WHOLE BUT NOT IN PART PURSUANT TO SECTION 3.5(A) OF THE WARRANT
        AGREEMENT, (III) THIS GLOBAL WARRANT MAY BE DELIVERED TO THE WARRANT
        AGENT FOR CANCELLATION

                                       16

<PAGE>

        PURSUANT TO SECTION 3.8 OF THE WARRANT AGREEMENT AND (IV) THIS GLOBAL
        WARRANT MAY BE TRANSFERRED TO A SUCCESSOR DEPOSITARY WITH THE PRIOR
        WRITTEN CONSENT OF AMERICAN TOWER CORPORATION (THE "COMPANY")."

               (iii) Unit Legend. Each Warrant issued prior to the Separation
        Date will bear a legend to the following effect unless otherwise agreed
        by the Company and the holder thereof:

               "THE WARRANTS EVIDENCED BY THIS CERTIFICATE ARE INITIALLY ISSUED
        AS PART OF AN ISSUANCE OF UNITS (THE "UNITS"), EACH OF WHICH CONSISTS OF
        $1,000 PRINCIPAL AMOUNT AT MATURITY OF THE 12.25% SENIOR SUBORDINATED
        DISCOUNT NOTES DUE 2008 (THE "NOTES") OF ESCROW CORP. AND ONE WARRANT TO
        PURCHASE 14.0953 SHARES, PAR VALUE $0.01 PER SHARE, OF AMERICAN TOWER
        CORPORATION.

               PRIOR TO THE EARLIEST TO OCCUR OF (I) 180 DAYS AFTER THE CLOSING
        OF THE OFFERING, (II) THE DATE ON WHICH A REGISTRATION STATEMENT FOR A
        REGISTERED EXCHANGE OFFER WITH RESPECT TO THE NOTES IS DECLARED
        EFFECTIVE UNDER THE SECURITIES ACT, (III) THE DATE A SHELF REGISTRATION
        STATEMENT WITH RESPECT TO THE WARRANTS IS DECLARED EFFECTIVE UNDER THE
        SECURITIES ACT, (IV) SUCH DATE AS CREDIT SUISSE FIRST BOSTON LLC IN ITS
        SOLE DISCRETION SHALL DETERMINE AND (V) IN THE EVENT OF A CHANGE OF
        CONTROL, THE DATE AMERICAN TOWER ESCROW CORPORATION (OR ITS SUCCESSOR)
        MAILS THE REQUISITE NOTICE TO THE HOLDERS, THE WARRANTS EVIDENCED BY
        THIS CERTIFICATE MAY NOT BE TRANSFERRED OR EXCHANGED SEPARATELY FROM,
        BUT MAY BE TRANSFERRED OR EXCHANGED ONLY TOGETHER WITH, THE NOTES."

               (iv) Regulation S Legend. Each Warrant that is a Registrable
        Security and issued pursuant to Regulation S shall bear the following
        legend in substantially the following form unless otherwise agreed by
        the Company and the holder thereof:

               "THIS WARRANT AND THE SECURITIES TO BE ISSUED UPON ITS EXERCISE
        HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT AND THE WARRANT MAY
        NOT BE EXERCISED BY OR ON BEHALF OF ANY U.S. PERSON UNLESS REGISTERED
        UNDER THE U.S. SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT")
        OR AN EXEMPTION FROM SUCH REGISTRATION IS AVAILABLE. IN ORDER TO
        EXERCISE THIS WARRANT, THE HOLDER MUST FURNISH TO THE COMPANY AND THE
        WARRANT AGENT EITHER (A) A WRITTEN CERTIFICATION THAT IT IS NOT A U.S.
        PERSON AND THE WARRANT IS NOT BEING EXERCISED ON BEHALF OF A U.S. PERSON
        OR (B) A WRITTEN OPINION OF COUNSEL TO THE EFFECT THAT THE SECURITIES
        DELIVERED UPON EXERCISE OF THE WARRANT HAVE BEEN REGISTERED UNDER THE
        SECURITIES ACT OR THAT THE DELIVERY OF SUCH SECURITIES IS EXEMPT FROM
        THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT. TERMS IN THIS
        LEGEND HAVE THE MEANINGS GIVEN TO THEM BY REGULATION S UNDER THE
        SECURITIES ACT."

        (h)    Cancellation and/or Adjustment of Global Warrants.

                                       17

<PAGE>

               At such time as all beneficial interests in a particular Global
Warrant have been exercised or exchanged for Definitive Warrants or a particular
Global Warrant has been exercised, redeemed, repurchased or canceled in whole
and not in part, each such Global Warrant shall be returned to or retained and
canceled by the Warrant Agent in accordance with Section 3.8 hereof. At any time
prior to such cancellation, if any beneficial interest in a Global Warrant is
exercised or exchanged for or transferred to a Person who will take delivery
thereof in the form of a beneficial interest in another Global Warrant or for
Definitive Warrants, the amount of Warrants represented by such Global Warrant
shall be reduced accordingly and an endorsement shall be made on such Global
Warrant by the Warrant Agent or by the Depositary at the direction of the
Warrant Agent to reflect such reduction; and if the beneficial interest is being
exchanged for or transferred to a Person who will take delivery thereof in the
form of a beneficial interest in another Global Warrant, such other Global
Warrant shall be increased accordingly and an endorsement shall be made on such
Global Warrant by the Warrant Agent or by the Depositary at the direction of the
Warrant Agent to reflect such increase.

        (i)    General Provisions Relating to Transfers and Exchanges.

               (i) To permit registrations of transfers and exchanges, the
        Company shall execute and the Warrant Agent shall countersign Global
        Warrants and Definitive Warrants upon the Company's order or at the
        Warrant Registrar's request.

               (ii) No service charge shall be made to a holder of a beneficial
        interest in a Global Warrant or to a holder of a Definitive Warrant for
        any registration of transfer or exchange, but the Company may require
        payment of a sum sufficient to cover any transfer tax or similar
        governmental charge payable in connection therewith.

               (iii) All Global Warrants and Definitive Warrants issued upon any
        registration of transfer or exchange of Global Warrants or Definitive
        Warrants shall be the duly authorized, executed and issued warrants for
        Common Stock of the Company, not subject to any preemptive rights, and
        entitled to the same benefits under this Warrant Agreement, as the
        Global Warrants or Definitive Warrants surrendered upon such
        registration of transfer or exchange.

               (iv) Prior to due presentment for the registration of a transfer
        of any Warrant, the Warrant Agent, and the Company may deem and treat
        the Person in whose name any Warrant is registered as the absolute owner
        of such Warrant for all purposes and none of the Warrant Agent, or the
        Company shall be affected by notice to the contrary.

               (v) The Warrant Agent shall countersign Global Warrants and
        Definitive Warrants in accordance with the provisions of Section 3.2
        hereof.

        (j)    Facsimile Submissions to Warrant Agent.

               All certifications, certificates and Opinions of Counsel required
to be submitted to the Warrant Registrar pursuant to this Section 3.5 to effect
a registration of transfer or exchange may be submitted by facsimile.

               Notwithstanding anything herein to the contrary, as to any
certificates and/or certifications delivered to the Warrant Registrar pursuant
to this Section 3.5, the Warrant Registrar's duties shall be limited to
confirming that any such certifications and certificates delivered to it are in
the form of Exhibits B and C attached hereto. The Warrant Registrar shall not be
responsible for confirming the truth or accuracy of representations made in any
such certifications or certificates. As to any Opinions

                                       18

<PAGE>

of Counsel delivered pursuant to this Section 3.5, the Warrant Registrar may
rely upon, and be fully protected in relying upon, such opinions.

        3.6.   REPLACEMENT WARRANTS.

               If any mutilated Warrant is surrendered to the Warrant Agent or
the Company and the Warrant Agent receives evidence to its satisfaction of the
destruction, loss or theft of any Warrant, the Company shall issue and the
Warrant Agent, upon receipt of a Warrant Countersignature Order, shall
countersign a replacement Warrant if the Warrant Agent's requirements are met.
If required by the Warrant Agent or the Company, an indemnity bond must be
supplied by the Holder that is sufficient in the judgment of the Warrant Agent
and the Company to protect the Company, the Warrant Agent, any Agent and any
agent for purposes of the countersignature from any loss that any of them may
suffer if a Warrant is replaced. The Company may charge for its expenses in
replacing a Warrant.

               Every replacement Warrant is an additional warrant of the Company
and shall be entitled to all of the benefits of this Warrant Agreement equally
and proportionately with all other Warrants duly issued hereunder.

        3.7.   TEMPORARY WARRANTS.

               Until certificates representing Warrants are ready for delivery,
the Company may prepare and the Warrant Agent, upon receipt of a Warrant
Countersignature Order, shall issue temporary Warrants. Temporary Warrants shall
be substantially in the form of certificated Warrants but may have variations
that the Company considers appropriate for temporary Warrants and as shall be
reasonably acceptable to the Warrant Agent. Without unreasonable delay, the
Company shall prepare and the Warrant Agent, as soon as practicable upon receipt
of the written order of the Company signed by an officer of the Company, shall
countersign definitive Warrants in exchange for temporary Warrants.

               Holders of temporary Warrants shall be entitled to all of the
benefits of this Warrant Agreement.

        3.8.   CANCELLATION.

               Subject to Section 3.5(h) hereof, the Company at any time may
deliver Warrants to the Warrant Agent for cancellation. The Warrant Registrar
and Warrant Paying Agent shall forward to the Warrant Agent any Warrants
surrendered to them for registration of transfer, exchange or exercise. The
Warrant Agent and no one else shall cancel all Warrants surrendered for
registration of transfer, exchange, exercise, replacement or cancellation and
shall dispose of such canceled Warrants in its customary manner. The Company may
not issue new Warrants to replace Warrants that have been exercised or that have
been delivered to the Warrant Agent for cancellation.

SECTION 4.          SEPARATION OF WARRANTS; TERMS OF WARRANTS; EXERCISE OF
                    WARRANTS

               (a)  The Notes and Warrants will not be separately transferable
until the Separation Date. Subject to the terms of this Agreement, each Warrant
holder shall have the right, which may be exercised during the period commencing
at the opening of business on January 29, 2006 until August 1, 2008 (the
"Exercise Period"), to receive from the Company the number of fully paid and
nonassessable Warrant Shares which the holder may at the time be entitled to
receive on exercise of such Warrants and payment of the Exercise Price (i) by
tendering Notes having an Accreted Value to the date of exercise

                                       19

<PAGE>

equal to the Exercise Price (ii) by tendering Warrants as set forth below, (iii)
by tendering any combination of Notes and Warrants or (iv) in cash in United
States dollars by wire transfer or by certified or official bank check payable
to the order of the Company the Exercise Price then in effect for such Warrant
Shares; provided that holders shall be able to exercise their Warrants only if a
registration statement relating to the Warrant Shares is then in effect, or the
exercise of such Warrants is exempt from the registration requirements of the
Securities Act, and such securities are qualified for sale or exempt from
qualification under the applicable securities laws of the states in which the
various holders of the Warrants or other persons to whom it is proposed that the
Warrant Shares be issued on exercise of the Warrants reside. Each holder may
exercise its right during the Exercise Period, to receive Warrant Shares on a
net basis, such that, without the exchange of any funds, the holder will receive
such number of Warrant Shares equal to the product of (A) the number of Warrant
Shares for which such Warrant is exercisable as of the date of exercise (if the
Exercise Price were being paid in cash) and (B) the Cashless Exercise Ratio. The
Cashless Exercise Ratio shall equal a fraction the numerator of which is the
Market Value per share of Common Stock minus the Exercise Price per share as of
the date of exercise and the denominator of which is the Market Value per share
on the date of exercise. Each Warrant not exercised on or prior to August 1,
2008 (the "Expiration Date") shall become void and all rights thereunder and all
rights in respect thereof under this agreement shall cease as of such time. No
adjustments as to dividends will be made upon exercise of the Warrants.
Notwithstanding the foregoing, if the Escrow Corp. Merger has not been
consummated and the Notes have been mandatorily redeemed pursuant to Section
3.08 of the Indenture (the "Redemption Date"), each Warrant shall become void
and all rights thereunder and all rights in respect thereof under this Agreement
shall cease as of the Redemption Date.

               (b)  In order to exercise all or any of the Warrants represented
by a Warrant Certificate, the holder thereof must deliver to the Warrant Agent
at its corporate trust office set forth in Section 15 hereof the Warrant
Certificate and the form of election to purchase on the reverse thereof duly
filled in and signed, which signature shall be medallion guaranteed by an
institution which is a member of a Securities Transfer Association recognized
signature guarantee program, and upon payment to the Warrant Agent for the
account of the Company of the Exercise Price, which is set forth in the form of
Warrant Certificate attached hereto as Exhibit A, as adjusted as herein
provided, for the number of Warrant Shares in respect of which such Warrants are
then exercised. Payment of the aggregate Exercise Price shall be made in the
manner provided in Section 4(a) hereof.

               (c)  Subject to the provisions of Section 5 hereof, upon
compliance with clause (b) above, the Warrant Agent shall deliver or cause to be
delivered with all reasonable dispatch, to or upon the written order of the
holder and in such name or names as the Warrant holder may designate, a
certificate or certificates for the number of whole Warrant Shares issuable upon
the exercise of such Warrants or other securities or property to which such
holder is entitled hereunder, together with cash as provided in Section 9
hereof; provided that if any consolidation, merger or lease or sale of assets is
proposed to be effected by the Company as described in Section 8(k) hereof, or a
tender offer or an exchange offer for shares of Common Stock shall be made, upon
such surrender of Warrants and payment of the Exercise Price as aforesaid, the
Warrant Agent shall, as soon as reasonably possible, deliver or cause to be
delivered the full number of Warrant Shares issuable upon the exercise of such
Warrants in the manner described in this sentence or other securities or
property to which such holder is entitled hereunder, together with cash as
provided in Section 9 hereof. Such certificate or certificates shall be deemed
to have been issued and any person so designated to be named therein shall be
deemed to have become a holder of record of such Warrant Shares as of the date
of the surrender of such Warrants and payment of the Exercise Price.

               (d)  The Warrants shall be exercisable, at the election of the
holders thereof, either in full or from time to time in part pursuant to the
terms of this Section 4. If less than all the Warrants

                                       20

<PAGE>

represented by a Warrant Certificate are exercised, such Warrant Certificate
shall be surrendered and a new Warrant Certificate of the same tenor and for the
number of Warrants which were not exercised shall be executed by the Company and
delivered to the Warrant Agent and the Warrant Agent shall countersign the new
Warrant Certificate, registered in such name or names as may be directed in
writing by the holder, and shall deliver the new Warrant Certificate to the
Person or Persons entitled to receive the same.

               (e)  All Warrant Certificates surrendered upon exercise of
Warrants shall be cancelled by the Warrant Agent. Such cancelled Warrant
Certificates shall then be disposed of by the Warrant Agent in its customary
manner. The Warrant Agent shall account promptly to the Company with respect to
Warrants exercised and concurrently pay to the Company all monies received by
the Warrant Agent for the purchase of the Warrant Shares through the exercise of
such Warrants.

               (f)  The Warrant Agent shall keep copies of this Agreement and
any notices given or received hereunder available for inspection by the holders
upon reasonable prior written notice during normal business hours at its office.
The Company shall supply the Warrant Agent from time to time with such numbers
of copies of this Agreement as the Warrant Agent may request.

               (g)  The Company has agreed pursuant to the Warrant Registration
Rights Agreement to file within 90 days after the issuance of the Warrants and
use its reasonable best efforts to make effective, subject to certain exceptions
detailed in the Warrant Registration Rights Agreement, on or before 180 days
after such date a shelf registration statement covering the resale of the
Warrants, the issuance by the Company's common stock upon the exercise of the
warrants resold pursuant to such registration statement and the resale of the
Warrant Shares by the holder thereof on the appropriate form under the
Securities Act, and to use its reasonable best efforts (subject to certain
"black-out" periods not to exceed 60 days in any calendar year subject to
extension for 30 days in certain circumstances) to keep such registration
statement continuously effective under the Securities Act, subject to certain
exceptions, until two years following the Closing Date.

               (h)  The holders of the warrants will have no right to vote on
matters submitted to the stockholders of the Company and will have no right to
receive dividends. The holders of the warrants will not be entitled to share in
the assets of the Company in the event of liquidation, dissolution or the
winding up of the Company. In the event a bankruptcy or reorganization is
commenced by or against the Company, a bankruptcy court may hold that
unexercised warrants are executory contracts which may be subject to rejection
by the Company with approval of the bankruptcy court, and the holders of the
warrants may, even if sufficient funds are available, receive nothing or a
lesser amount as a result of any such bankruptcy case than they would be
entitled to if they had exercised their warrants prior to the commencement of
any such case.

SECTION 5.          PAYMENT OF TAXES.

               The Company will pay all documentary stamp taxes attributable to
the initial issuance of Warrant Shares upon the exercise of Warrants; provided
that the Company shall not be required to pay any tax or taxes which may be
payable in respect of any transfer involved in the issue of any Warrant
Certificates or any certificates for Warrant Shares in a name other than that of
the registered holder of a Warrant Certificate surrendered upon the exercise of
a Warrant, and the Company shall not be required to issue or deliver such
Warrant Certificates unless or until the person or persons requesting the
issuance thereof shall have paid to the Company the amount of such tax or shall
have established to the satisfaction of the Company that such tax has been paid;
provided further that the Company shall not be required to pay any tax or taxes
which may be payable in the event of a taxable distribution to holders of the
Company's common stock that results in an adjustment to the number of Warrant
Shares or other

                                       21

<PAGE>

consideration for which a Warrant may be exercised, and results in the holders
of the Warrants to be deemed to have received a distribution subject to United
States federal income tax as a dividend.

SECTION 6.          RESERVATION OF WARRANT SHARES.

               (a)  The Company will at all times reserve and keep available,
free from preemptive rights, out of the aggregate of its authorized but unissued
Common Stock or its authorized and issued Common Stock held in its treasury, for
the purpose of enabling it to satisfy any obligation to issue Warrant Shares
upon exercise of Warrants, the maximum number of shares of Common Stock which
may then be deliverable upon the exercise of all outstanding Warrants.

               (b)  The Company or, if appointed, the transfer agent for the
Common Stock (the "Transfer Agent") and every subsequent transfer agent for any
shares of the Company's capital stock issuable upon the exercise of any of the
rights of purchase aforesaid will be irrevocably authorized and directed at all
times to reserve such number of authorized shares as shall be required for such
purpose. The Company will keep a copy of this Agreement on file with the
Transfer Agent and with every subsequent transfer agent for any shares of the
Company's capital stock issuable upon the exercise of the rights of purchase
represented by the Warrants. The Warrant Agent is hereby irrevocably authorized
to requisition from time to time from such Transfer Agent the stock certificates
required to honor outstanding Warrants upon exercise thereof in accordance with
the terms of this Agreement. The Company will supply such Transfer Agent with
duly executed certificates for such purposes and will provide or otherwise make
available any cash which may be payable as provided in Section 9 hereof. The
Company will furnish such Transfer Agent a copy of all notices of adjustments,
and certificates related thereto, transmitted to each holder pursuant to Section
11 hereof.

               (c)  The Company covenants that all Warrant Shares which may be
issued upon exercise of Warrants will, upon issue, be fully paid, nonassessable,
free of preemptive rights and free from all taxes, liens, charges and security
interests with respect to the issuance thereof.

SECTION 7.          OBTAINING STOCK EXCHANGE LISTINGS.

               The Company will from time to time take all action which may be
necessary so that the Warrant Shares, immediately upon their issuance upon the
exercise of Warrants, will be listed on the principal securities exchanges,
automated quotation systems or other markets within the United States of
America, if any, on which other shares of Common Stock are then listed, if any.

SECTION 8.          ADJUSTMENT OF EXERCISE PRICE AND NUMBER OF WARRANT SHARES
                    ISSUABLE.

               The Exercise Price and the number of Warrant Shares issuable upon
the exercise of each Warrant are subject to adjustment from time to time upon
the occurrence of the events enumerated in this Section 8. For purposes of this
Section 8, "Common Stock" means shares now or hereafter authorized of any class
of common stock of the Company and any other stock of the Company, however
designated, that has the right (subject to any prior rights of any class or
series of preferred stock) to participate in any distribution of the assets or
earnings of the Company without limit as to per share amount.

               (a)  Adjustment for Change in Capital Stock.

                                       22

<PAGE>

               If the Company (i) pays a dividend or makes a distribution on its
Common Stock in shares of its Common Stock, (ii) subdivides its outstanding
shares of Common Stock into a greater number of shares, (iii) combines its
outstanding shares of Common Stock into a smaller number of shares, (iv) makes a
distribution on its Common Stock in shares of its capital stock other than
Common Stock or (v) issues by reclassification of its Common Stock any shares of
its capital stock, then the Exercise Price in effect immediately prior to such
action shall be proportionately adjusted so that the holder of any Warrant
thereafter exercised may receive the aggregate number and kind of shares of
capital stock of the Company which he would have owned immediately following
such action if such Warrant had been exercised immediately prior to such action.

               The adjustment shall become effective immediately after the
record date in the case of a dividend or distribution and immediately after the
effective date in the case of a subdivision, combination or reclassification.
If, after an adjustment, a holder of a Warrant upon exercise of it may receive
shares of two or more classes of capital stock of the Company, the Company shall
determine, in good faith, the allocation of the adjusted Exercise Price between
the classes of capital stock. After such allocation, the exercise privilege and
the Exercise Price of each class of capital stock shall thereafter be subject to
adjustment on terms comparable to those applicable to Common Stock in this
Section 8. Such adjustment shall be made successively whenever any event listed
above shall occur.

               (b)  Adjustment for Rights Issue.

               If the Company distributes any rights, options or warrants to all
holders of its Common Stock entitling them for a period expiring within 45 days
after the record date mentioned below to purchase shares of Common Stock at a
price per share less than the Fair Value per share on that record date, the
Exercise Price shall be adjusted in accordance with the formula:

                        O + N X P
                            -----
            E' = E X          M
                     ---------------
                         O + N
where:

                E'       =        the adjusted Exercise Price.

                E        =        the current Exercise Price.

                O        =        the number of shares of Common Stock
                                  outstanding on the record date.

                N        =        the number of additional shares of Common
                                  Stock issued pursuant to such rights,
                                  options or warrants.

                P        =        the aggregate price per share of the
                                  additional shares.

                M        =        the Fair Value per share of Common Stock on
                                  the record date.

               The adjustment shall be made successively whenever any such
rights, options or warrants are issued and shall become effective immediately
after the record date for the determination of stockholders entitled to receive
the rights, options or warrants. If at the end of the period during which such
rights, options or warrants are exercisable, not all rights, options or warrants
shall have been

                                       23

<PAGE>

exercised, the Exercise Price shall be immediately readjusted to what it would
have been if "N" in the above formula had been the number of shares actually
issued.

               (c)  Adjustment for Other Distributions.

               If the Company distributes to all holders of its Common Stock any
of its assets or debt securities or any rights or warrants to purchase debt
securities of the Company, the Exercise Price shall be adjusted in accordance
with the formula:

                         M  -  F
           E' =  E  X   ---------
                            M
where:

             E'       =        the adjusted Exercise Price.

             E        =        the current Exercise Price.

             M        =        the Fair Value per share of Common Stock on the
                               record date mentioned below.

             F        =        the fair market value on the record date
                               of the assets, securities, rights or
                               warrants to be distributed in respect of one
                               share of Common Stock as determined in good
                               faith by the Board of Directors of the
                               Company (the "Board of Directors").

               The adjustment shall be made successively whenever any such
distribution is made and shall become effective immediately after the record
date for the determination of stockholders entitled to receive the distribution.

               This Section 8(c) does not apply to cash dividends or cash
distributions paid out of consolidated current or retained earnings as shown on
the books of the Company prepared in accordance with generally accepted
accounting principles. Also, this Section 8(c) does not apply to rights, options
or warrants referred to in Section 8(b) hereof.

               (d)  Adjustment for Common Stock Issue.

               If the Company issues shares of Common Stock for a consideration
per share less than the Fair Value per share on the date the Company fixes the
offering price of such additional shares, the Exercise Price shall be adjusted
in accordance with the formula:

                            P
                           ---
           E' = E  X  O  +  M
                    -----------
                      A
where:

              E'       =        the adjusted Exercise Price.

                                       24

<PAGE>

              E        =        the then current Exercise Price.

              O        =        the number of shares outstanding immediately
                                prior to the issuance of such additional
                                shares.

              P        =        the aggregate consideration received for the
                                issuance of such additional
                                shares.

              M        =        the Fair Value per share on the date of issuance
                                of such additional shares.

              A        =        the number of shares outstanding
                                immediately after the issuance of such
                                additional shares.

               The adjustment shall be made successively whenever any such
issuance is made, and shall become effective immediately after such issuance.

               This subsection (d) does not apply to:

                    (1) any of the transactions described in subsections (a),
        (b), (c) and (e) of this Section 8,

                    (2) the exercise of Warrants, or the conversion or exchange
        of other securities convertible or exchangeable for Common Stock the
        issuance of which caused an adjustment to be made under Section 8(e),

                    (3) Common Stock issued to the Company's employees (or
        employees of its subsidiaries) under bona fide employee benefit plans
        adopted by the Board of Directors and approved by the holders of Common
        Stock when required by law, if such Common Stock would otherwise be
        covered by this subsection (d) (but only to the extent that the
        aggregate number of shares excluded hereby and issued after the date of
        this Warrant Agreement shall not exceed 10% of the Common Stock
        outstanding at the time of the adoption of each such plan, exclusive of
        anti-dilution adjustments thereunder),

                    (4) Common Stock issued to shareholders of any person which
        merges into the Company, or with a subsidiary of the Company, in
        proportion to their stock holdings of such person immediately prior to
        such merger, upon such merger, provided that if such person is an
        Affiliate of the Company, the Board of Directors shall have obtained a
        fairness opinion from a nationally recognized investment banking,
        appraisal or valuation firm, which is not an Affiliate of the Company,
        stating that the consideration received in such merger is fair to the
        Company from a financial point of view, or

                    (5) the issuance of shares of Common Stock pursuant to
        rights, options, warrants or convertible securities which were
        originally issued in a Non-Affiliate Sale (as defined below) together
        with one or more other securities as part of a unit at a price per unit.

               (e)  Adjustment for Convertible Securities Issue.

               If the Company issues any securities convertible into or
exchangeable for Common Stock (other than securities issued in transactions
described in subsections (b) and (c) of this Section 8) for a consideration per
share of Common Stock initially deliverable upon conversion or exchange of such

                                       25

<PAGE>

securities less than the Fair Value per share on the date of issuance of such
securities, the Exercise Price shall be adjusted in accordance with this
formula:

                                 P
                                ---
                             O + M
            E'   =    E X  ----------
                             O + D
where:

                 E'     =    the adjusted Exercise Price.

                 E      =    the then current Exercise Price.

                 O      =    the number of shares  outstanding  immediately
                             prior to the  issuance  of such securities.

                 P      =    the aggregate consideration received for the
                             issuance of such securities.

                 M      =    the Fair Value per share on the date of issuance
                             of such securities.

                 D      =    the maximum number of shares deliverable upon
                             conversion or in exchange for such securities at
                             the initial conversion or exchange rate.

               The adjustment shall be made successively whenever any such
               issuance is made, and shall become effective immediately after
               such issuance.

               If all of the Common Stock deliverable upon conversion or
exchange of such securities have not been issued when such securities are no
longer outstanding, then the Exercise Price shall promptly be readjusted to the
Exercise Price which would then be in effect had the adjustment upon the
issuance of such securities been made on the basis of the actual number of
shares of Common Stock issued upon conversion or exchange of such securities.

               This subsection (e) does not apply to convertible securities
issued to shareholders of any person which merges into the Company, or with a
subsidiary of the Company, in proportion to their stock holdings of such person
immediately prior to such merger, upon such merger, provided that if such person
is an Affiliate of the Company, the Board of Directors shall have obtained a
fairness opinion from a nationally recognized investment banking, appraisal or
valuation firm, which is not an Affiliate of the Company, stating that the
consideration received in such merger is fair to the Company from a financial
point of view.

               (f)  Consideration Received.

               For purposes of any computation respecting consideration received
pursuant to subsections (d), and (e) of this Section 8, the following shall
apply:

                    (1) in the case of the issuance of shares of Common Stock
for cash, the consideration shall be the amount of such cash, provided that in
no case shall any deduction be made for any commissions, discounts or other
expenses incurred by the Company for any underwriting of the issue or otherwise
in connection therewith;

                                       26

<PAGE>

                    (2) in the case of the issuance of shares of Common Stock
for a consideration in whole or in part other than cash, the consideration other
than cash shall be deemed to be the fair market value thereof as determined in
good faith by the Board of Directors (irrespective of the accounting treatment
thereof), whose determination shall be conclusive, and described in a Board
resolution which shall be filed with the Warrant Agent;

                    (3) in the case of the issuance of securities convertible
into or exchangeable for shares, the aggregate consideration received therefor
shall be deemed to be the consideration received by the Company for the issuance
of such securities plus the additional minimum consideration, if any, to be
received by the Company upon the conversion or exchange thereof (the
consideration in each case to be determined in the same manner as provided in
clauses (1) and (2) of this subsection); and

                    (4) in the case of the issuance of shares of Common Stock
pursuant to rights, options or warrants which rights, options or warrants were
originally issued together with one or more other securities as part of a unit
at a price per unit, the consideration shall be deemed to be the fair value of
such rights, options or warrants at the time of issuance thereof as determined
in good faith by the Board of Directors whose determination shall be conclusive
and described in a Board resolution which shall be filed with the Warrant Agent
plus the additional minimum consideration, if any, to be received by the Company
upon the exercise, conversion or exchange thereof (as determined in the same
manner as provided in clauses (1) and (2) of this subsection).

               (g)  When De Minimis Adjustment May Be Deferred.

               No adjustment in the Exercise Price need be made unless the
adjustment would require an increase or decrease of at least 1% in the Exercise
Price; provided however, that any adjustments that are not made shall be carried
forward and taken into account in any subsequent adjustment. All calculations
under this Section 8 shall be made to the nearest cent or to the nearest
1/10,000th of a share, as the case may be, it being understood that no such
rounding shall be made under subsection (o).

               (h)  When No Adjustment Required.

               No adjustment need be made for a transaction referred to Section
8(a), (b), (c), (d), (e) or (f) hereof, if Warrant holders are to participate
(without being required to exercise their Warrants) in the transaction on a
basis and with notice that the Board of Directors determines to be fair and
appropriate in light of the basis and notice on which holders of Common Stock
participate in the transaction. No adjustment need be made for (i) rights to
purchase Common Stock pursuant to a Company plan for reinvestment of dividends
or interest (ii) a change in the par value or no par value of the Common Stock
or (iii) the issuance by the Company of warrants to the Initial Purchasers on or
about January 29, 2003. To the extent the Warrants become convertible into cash,
no adjustment need be made thereafter as to the cash. Interest will not accrue
on the cash. No adjustment shall be made pursuant to this Section 8 if such
adjustment causes the Exercise Price to fall below the par value per Warrant
Share.

               (i)  Notice of Adjustment.

               Whenever the Exercise Price is adjusted, the Company shall
provide the notices required by Section 10 hereof.

               (j)  Notice of Certain Transactions.

                                       27

<PAGE>

               If (i) the Company takes any action that would require an
adjustment in the Exercise Price pursuant to Section 8(a), (b), (c), (d), (e) or
(f) hereof and if the Company does not arrange for Warrant holders to
participate pursuant to Section 8(h) hereof, (ii) the Company takes any action
that would require a supplemental Warrant Agreement pursuant to Section 8(j)
hereof or (iii) there is a liquidation or dissolution of the Company, then the
Company shall mail to Warrant holders a notice stating the proposed record date
for a dividend or distribution or the proposed effective date of a subdivision,
combination, reclassification, consolidation, merger, transfer, lease,
liquidation or dissolution. The Company shall mail the notice at least 15 days
before such date. Failure to mail the notice or any defect in it shall not
affect the validity of the transaction.

               (k)  Reorganization of Company.

               Immediately after the date hereof, if the Company consolidates or
merges with or into, or transfers or leases all or substantially all its assets
to, any person, upon consummation of such transaction the Warrants shall
automatically become exercisable if such transaction occurs within the Exercise
Period for the kind and amount of securities, cash or other assets which the
holder of a Warrant would have owned immediately after the consolidation,
merger, transfer or lease if the holder had exercised the Warrant immediately
before the effective date of the transaction. Concurrently with the consummation
of such transaction, the corporation formed by or surviving any such
consolidation or merger if other than the Company, or the person to which such
sale or conveyance shall have been made, shall enter into (i) a supplemental
Warrant Agreement so providing and further providing for adjustments which shall
be as nearly equivalent as may be practical to the adjustments provided for in
this Section 8(k) and (ii) a supplement to the Warrant Registration Rights
Agreement providing for the assumption of the Company's obligations thereunder.
The successor Company shall mail to Warrant holders a notice describing the
supplemental Warrant Agreement and Warrant Registration Rights Agreement. If the
issuer of securities deliverable upon exercise of Warrants under the
supplemental Warrant Agreement is an affiliate of the formed, surviving,
transferee or lessee corporation, that issuer shall join in the supplemental
Warrant Agreement and Warrant Registration Rights Agreement. If this Section
8(k) applies, Sections 8(a), (b), (c), (d), (e) and (f) hereof do not apply.

               (l)  Company Determination Final.

               Any determination that the Company or the Board of Directors must
make pursuant to Section 8(a), (c), (d), (e), (f), (g), (h) or (i) hereof is
conclusive.

               (m)  Warrant Agent's Disclaimer.

               The Warrant Agent has no duty to determine when an adjustment
under this Section 8 should be made, how it should be made or what it should be.
The Warrant Agent has no duty to determine whether any provisions of a
supplemental Warrant Agreement under Section 8(k) hereof are correct. The
Warrant Agent makes no representation as to the validity or value of any
securities or assets issued upon exercise of Warrants. The Warrant Agent shall
not be responsible for the Company's failure to comply with this Section 8.

               (n)  When Issuance or Payment May Be Deferred.

               In any case in which this Section 8 shall require that an
adjustment in the Exercise Price be made effective as of a record date for a
specified event, the Company may elect to defer until the occurrence of such
event (i) issuing to the holder of any Warrant exercised after such record date
the Warrant Shares and other capital stock of the Company, if any, issuable upon
such exercise over and

                                       28

<PAGE>

above the Warrant Shares and other capital stock of the Company, if any,
issuable upon such exercise on the basis of the Exercise Price and (ii) paying
to such holder any amount in cash in lieu of a fractional share pursuant to
Section 10 hereof; provided that the Company shall deliver to such holder a due
bill or other appropriate instrument evidencing such holder's right to receive
such additional Warrant Shares, other capital stock and cash upon the occurrence
of the event requiring such adjustment.

               (o)  Adjustment in Number of Shares.

               Upon each adjustment of the Exercise Price pursuant to this
Section 8, each Warrant outstanding prior to the making of the adjustment in the
Exercise Price shall thereafter evidence the right to receive upon payment of
the adjusted Exercise Price that number of shares of Common Stock (calculated to
the nearest hundredth) obtained from the following formula:

               N' = N  X E
                        ---
                         E'
where:

               N'   =   the adjusted number of Warrant Shares issuable upon
                        exercise of a Warrant by payment of the adjusted
                        Exercise Price.

               N    =   the number or Warrant Shares previously issuable upon
                        exercise of a Warrant by payment of the Exercise Price
                        prior to adjustment.

               E'   =   the adjusted Exercise Price.

               E    =   the Exercise Price prior to adjustment.

               (p)  Form of Warrants.

               Irrespective of any adjustments in the Exercise Price or the
number or kind of shares purchasable upon the exercise of the Warrants, Warrants
theretofore or thereafter issued may continue to express the same price and
number and kind of shares as are stated in the Warrants initially issuable
pursuant to this Agreement.

SECTION 9.          FRACTIONAL INTERESTS.

               The Company shall not be required to issue fractional Warrant
Shares on the exercise of Warrants. If more than one Warrant shall be presented
for exercise in full at the same time by the same holder, the number of full
Warrant Shares which shall be issuable upon the exercise thereof shall be
computed on the basis of the aggregate number of Warrant Shares purchasable on
exercise of the Warrants so presented. If any fraction of a Warrant Share would,
except for the provisions of this Section 9, be issuable on the exercise of any
Warrants (or specified portion thereof), the Company shall pay an amount in cash
equal to the Fair Value per Warrant Share, as determined on the day immediately
preceding the date the Warrant is presented for exercise, multiplied by such
fraction, computed to the nearest whole U.S. cent.

                                       29

<PAGE>

SECTION 10.         NOTICES TO WARRANT HOLDERS.

               (a)  Upon any adjustment of the Exercise Price pursuant to
Section 8 hereof, the Company shall promptly thereafter (i) cause to be filed
with the Warrant Agent a certificate of a firm of independent public accountants
of recognized standing selected by the Board of Directors of the Company (who
may be the regular auditors of the Company) setting forth the Exercise Price
after such adjustment and setting forth in reasonable detail the method of
calculation and the facts upon which such calculations are based and setting
forth the number of Warrant Shares (or portion thereof) issuable after such
adjustment in the Exercise Price, upon exercise of a Warrant and payment of the
adjusted Exercise Price, which certificate shall be conclusive evidence of the
correctness of the matters set forth therein, and (ii) cause to be given to each
of the registered holders of Warrants at the address appearing on the Warrant
register for each such registered holder written notice of such adjustments by
first-class mail, postage prepaid. Where appropriate, such notice may be given
in advance and included as a part of the notice required to be mailed under the
other provisions of this Section 10.

               (b)  In case:

               (i)  the Company shall authorize the issuance to all holders of
        shares of Common Stock of rights, options or warrants to subscribe for
        or purchase shares of Common Stock or of any other subscription rights
        or warrants;

               (ii) the Company shall authorize the distribution to all holders
        of shares of Common Stock of evidences of its indebtedness or assets
        (other than dividends or cash distributions paid out of consolidated
        current or retained earnings as shown on the books of the Company
        prepared in accordance with generally accepted accounting principles or
        dividends payable in shares of Common Stock or distributions referred to
        in Section 10(a) hereof);

               (iii) of any consolidation or merger to which the Company is a
        party and for which approval of any stockholders of the Company is
        required, or of the conveyance or transfer of the properties and assets
        of the Company substantially as an entirety, or of any reclassification
        or change of Common Stock issuable upon exercise of the Warrants (other
        than a change in par value, or from par value to no par value, or from
        no par value to par value, or as a result of a subdivision or
        combination), or a tender offer or exchange offer for shares of Common
        Stock;

               (iv) of the voluntary or involuntary dissolution, liquidation or
        winding up of the Company; or

               (v)  the Company proposes to take any action (other than actions
        of the character described in Section 8(a) hereof) which would require
        an adjustment of the Exercise Price pursuant to Section 8 hereof;

then the Company shall cause to be filed with the Warrant Agent and shall cause
to be given to each of the registered holders of Warrants at his address
appearing on the Warrant register, at least 20 days (or 10 days in any case
specified in clauses (i) or (ii) above) prior to the applicable record date
hereinafter specified, or promptly in the case of events for which there is no
record date, by first-class mail, postage prepaid, a written notice stating (x)
the date as of which the holders of record of shares of Common Stock to be
entitled to receive any such rights, options, warrants or distribution are to be
determined, (y) the initial expiration date set forth in any tender offer or
exchange offer for shares of Common Stock, or (z) the date on which any such
consolidation, merger, conveyance, transfer, dissolution, liquidation or winding
up is expected to become effective or consummated, and the date as of which it
is expected that holders of record of shares of Common Stock shall be entitled
to exchange such shares for securities or other property, if any, deliverable
upon such reclassification, consolidation, merger, conveyance, transfer,

                                       30

<PAGE>

dissolution, liquidation or winding up. The failure to give the notice required
by this Section 11 or any defect therein shall not affect the legality or
validity of any distribution, right, option, warrant, consolidation, merger,
conveyance, transfer, dissolution, liquidation or winding up, or the vote upon
any action.

               (c)  Nothing contained in this Agreement or in any of the Warrant
        Certificates shall be construed as conferring upon the holders of
        Warrants the right to vote or to consent or to receive notice as
        stockholders in respect of the meetings of stockholders or the election
        of directors of the Company or any other matter, or any rights
        whatsoever as stockholders of the Company.

SECTION 11.         MERGER, CONSOLIDATION OR CHANGE OF NAME OF WARRANT AGENT.

               (g)  Any corporation into which the Warrant Agent may be merged
or with which it may be consolidated, or any corporation resulting from any
merger or consolidation to which the Warrant Agent shall be a party, or any
corporation succeeding to all or substantially all of the business of the
Warrant Agent, shall be the successor to the Warrant Agent hereunder without the
execution or filing of any paper or any further act on the part of any of the
parties hereto, provided that such corporation would be eligible for appointment
as a successor warrant agent under the provisions of Section 13 hereof. In case
at the time such successor to the Warrant Agent shall succeed to the agency
created by this Agreement, and in case at that time any of the Warrant
Certificates shall have been countersigned but not delivered, any such successor
to the Warrant Agent may adopt the countersignature of the original Warrant
Agent; and in case at that time any of the Warrant Certificates shall not have
been countersigned, any successor to the Warrant Agent may countersign such
Warrant Certificates either in the name of the predecessor Warrant Agent or in
the name of the successor to the Warrant Agent; and in all such cases such
Warrant Certificates shall have the full force and effect provided in the
Warrant Certificates and in this Agreement.

               (h)  In case at any time the name of the Warrant Agent shall be
changed and at such time any of the Warrant Certificates shall have been
countersigned but not delivered, the Warrant Agent whose name has been changed
may adopt the countersignature under its prior name, and in case at that time
any of the Warrant Certificates shall not have been countersigned, the Warrant
Agent may countersign such Warrant Certificates either in its prior name or in
its changed name, and in all such cases such Warrant Certificates shall have the
full force and effect provided in the Warrant Certificates and in this
Agreement.

SECTION 12.         WARRANT AGENT.

               The Warrant Agent undertakes only those duties and obligations
specifically imposed on it by this Agreement upon the following terms and
conditions, by all of which the Company and the holders of Warrants, by their
acceptance thereof, shall be bound:

               (a)  The statements contained herein and in the Warrant
Certificates shall be taken as statements of the Company and the Warrant Agent
assumes no responsibility for the correctness of any of the same except such as
describe the Warrant Agent or action taken or to be taken by it. The Warrant
Agent assumes no responsibility with respect to the distribution of the Warrant
Certificates except as herein otherwise provided.

                                       31

<PAGE>

               (b)  The Warrant Agent shall not be responsible for any failure
of the Company to comply with any of the covenants contained in this Agreement
or in the Warrant Certificates to be complied with by the Company.

               (c)  The Warrant Agent may consult at any time with counsel
satisfactory to it (who may be counsel for the Company) and the Warrant Agent
shall incur no liability or responsibility to the Company or to any holder of
any Warrant Certificate in respect of any action taken, suffered or omitted by
it hereunder in good faith and in accordance with the opinion or the advice of
such counsel.

               (d)  The Warrant Agent shall incur no liability or responsibility
to the Company or to any holder of any Warrant Certificate for any action taken
in reliance on any Warrant Certificate, certificate of shares, notice,
resolution, waiver, consent, order, certificate, or other paper, document or
instrument (whether in original or facsimile form) believed by it to be genuine
and to have been signed, sent or presented by the proper party or parties. The
Warrant Agent need not investigate any fact or matter stated in such document.

               (e)  The Company agrees to pay to the Warrant Agent reasonable
compensation for all services rendered by the Warrant Agent in the execution of
this Agreement, to reimburse the Warrant Agent for all expenses, taxes and
governmental charges and other charges of any kind and nature incurred by the
Warrant Agent in the execution of this Agreement. The Company shall indemnify
the Warrant Agent and its agents, employees, officers, directors and
shareholders for, and hold same harmless against, any and all losses,
liabilities, claims, damages or expenses (including without limitation
reasonable attorney's fees and expenses) incurred by it arising out of or in
connection with the acceptance or administration of its duties under this
Warrant Agreement, including the costs and expenses of enforcing this Warrant
Agreement against the Company and defending itself against any claim (whether
asserted by the Company or any Holder or any other person) or liability in
connection with the exercise or performance of any of its powers or duties
hereunder, except to the extent any such loss, liability or expense is
determined by a court of competent jurisdiction to have been cause by its gross
negligence or willful misconduct. The Warrant Agent shall notify the Company
promptly of any claim for which it may seek indemnity. Failure by the Warrant
Agent to so notify the Company shall not relieve the Company of its obligations
hereunder. At the Warrant Agent's sole discretion, the Company shall defend the
claim and the Warrant Agent shall cooperate in the defense at the Company's
expense. The Warrant Agent may have separate counsel and the Company shall pay
the reasonable fees and expenses of such counsel. The Company need not pay for
any settlement made without its consent, which consent shall not be unreasonably
withheld. The benefits of this Section shall survive termination of this
Agreement or change of Warrant Agent.

               (f)  The Warrant Agent shall be under no obligation to institute
any action, suit or legal proceeding or to take any other action likely to
involve expense unless the Company or one or more registered holders of Warrants
shall furnish the Warrant Agent with reasonable security and indemnity
satisfactory to it for any costs and expenses which may be incurred, but this
provision shall not affect the power of the Warrant Agent to take such action as
it may consider proper, whether with or without any such security or indemnity.
All rights of action under this Agreement or under any of the Warrants may be
enforced by the Warrant Agent without the possession of any of the Warrant
Certificates or the production thereof at any trial or other proceeding relative
thereto, and any such action, suit or proceeding instituted by the Warrant Agent
shall be brought in its name as Warrant Agent and any recovery of judgment shall
be for the ratable benefit of the registered holders of the Warrants, as their
respective rights or interests may appear.

                                       32

<PAGE>

               (g)  The Warrant Agent, and any stockholder, director, officer or
employee of it, may buy, sell or deal in any of the Warrants or other securities
of the Company or become pecuniarily interested in any transaction in which the
Company may be interested, or contract with or lend money to the Company or
otherwise act as fully and freely as though it were not Warrant Agent under this
Agreement. Nothing herein shall preclude the Warrant Agent from acting in any
other capacity for the Company or for any other legal entity.

               (h)  The Warrant Agent shall act hereunder solely as agent for
the Company, and its duties shall be determined solely by the provisions hereof.
The Warrant Agent shall not be liable for anything which it may do or refrain
from doing in connection with this Agreement except for its own gross negligence
or willful misconduct.

               (i)  The Warrant Agent shall not at any time be under any duty or
responsibility to any holder of any Warrant Certificate to make or cause to be
made any adjustment of the Exercise Price or number of the Warrant Shares or
other securities or property deliverable as provided in this Agreement, or to
determine whether any facts exist which may require any of such adjustments, or
with respect to the nature or extent of any such adjustments, when made, or with
respect to the method employed in making the same. The Warrant Agent shall not
be accountable with respect to the validity or value or the kind or amount of
any Warrant Shares or of any securities or property which may at any time be
issued or delivered upon the exercise of any Warrant or with respect to whether
any such Warrant Shares or other securities will when issued be validly issued
and fully paid and nonassessable, and makes no representation with respect
thereto.

               (i)  The Warrant Agent shall not be required to, and shall not,
expend or risk any of its own funds or otherwise incur any financial liability
in the performance of any of its duties hereunder.

               (j)  In no event shall the Warrant Agent be liable for any
consequential, punitive or special damages, or for the acts or omissions of its
nominees, correspondents, designees, subagents or subcustodians.

               (k)  The Warrant Agent shall not incur any liability for not
performing any act or fulfilling any duty, obligation or responsibility
hereunder by reason of any occurrence beyond the control of the Warrant Agent
(including but not limited to any act or provision of any present or future law
or regulation or governmental authority, any act of God or war, or the
unavailability of the Federal Reserve Bank wire or telex or other wire or
communication facility).

               (l)  In the event of any ambiguity or uncertainty hereunder or in
any notice, instruction or other communication received by the Warrant Agent
hereunder, the Warrant Agent may, in its sole discretion, refrain from taking
any action other than retain possession of the Warrant Shares, unless the
Warrant Agent receives written instructions, signed by the Company, which
eliminates such ambiguity or uncertainty.

SECTION 13.         CHANGE OF WARRANT AGENT.

               If the Warrant Agent shall become incapable of acting as Warrant
Agent, the Company shall appoint a successor to such Warrant Agent. If the
Company shall fail to make such appointment within a period of 30 days after it
has been notified in writing of such incapacity by the Warrant Agent or

                                       33

<PAGE>

by the registered holder of a Warrant Certificate, then the registered holder of
any Warrant or the Warrant Agent may petition at the expense of the Company to
any court of competent jurisdiction for the appointment of a successor to the
Warrant Agent. Pending appointment of a successor to such Warrant Agent, either
by the Company or by such a court, the duties of the Warrant Agent shall be
carried out by the Company. The holders of a majority of the unexercised
Warrants shall be entitled at any time to remove the Warrant Agent and appoint a
successor to such Warrant Agent. Such successor to the Warrant Agent need not be
approved by the Company or the former Warrant Agent. After appointment the
successor to the Warrant Agent shall be vested with the same powers, rights,
duties and responsibilities as if it had been originally named as Warrant Agent
without further act or deed; provided that the former Warrant Agent shall
deliver and transfer to the successor to the Warrant Agent any property at the
time held by it hereunder and execute and deliver any further assurance,
conveyance, act or deed necessary for the purpose. Failure to give any notice
provided for in this Section 13, however, or any defect therein, shall not
affect the legality or validity of the appointment of a successor to the Warrant
Agent.

SECTION 14.         REPORTS.

               (a)  Whether or not required by the rules and regulations of the
Commission, so long as any Warrants or the Warrant Shares are outstanding, the
Company shall make available to the Warrant Agent and the holders of Warrants or
Warrant Shares (i) all quarterly and annual financial information that would be
required to be contained in a filing with the Commission on Forms 10-Q and 10-K
if the Company were required to file such Forms, including a "Management's
Discussion and Analysis of Financial Condition and Results of Operations" and,
with respect to the annual information only, a report thereon by the Company's
certified independent accountants and (ii) all current reports that would be
required to be filed with the Commission on Form 8-K if the Company were
required to file such reports. In addition, whether or not required by the rules
and regulations of the Commission, the Company shall file a copy of all such
information and reports with the Commission for public availability (unless the
Commission shall not accept such a filing) and make such information available
to securities analysts and prospective investors upon request. Delivery of such
reports, information and documents to the Warrant Agent is for informational
purposes only and the Warrant Agent's receipt of such shall not constitute
constructive notice of any information contained therein or determinable from
information contained therein, including the Company's compliance with any of
its covenants hereunder (as to which the Warrant Agent is entitled to rely
exclusively on Officers' Certificates).

               (b)  The Company shall provide the Warrant Agent with a
sufficient number of copies of all such reports that the Warrant Agent may be
required to deliver to the holders of the Warrants and the Warrant Shares under
this Section 14.

SECTION 15.         NOTICES TO COMPANY AND WARRANT AGENT.

               Any notice or demand authorized by this Agreement to be given or
made by the Warrant Agent or by the registered holder of any Warrant to or on
the Company shall be sufficiently given or made when received if deposited in
the mail, first class or registered, postage prepaid, addressed (until another
address is filed in writing by the Company with the Warrant Agent) as follows:

                          American Tower Corporation
                          116 Huntington Avenue, 11th Floor
                          Boston, MA 02116
                          Telecopier No.: (617) 375-7575
                          Attention: Chief Financial Officer and Treasurer and

                                       34

<PAGE>

                          Executive Vice President and General Counsel

                 With a copy to:

                    Palmer & Dodge LLP
                    111 Huntington Avenue
                    Boston, MA 02199
                    Telecopier No.: (617) 227-4420
                    Attention: Matthew J. Gardella, Esq.

               In case the Company shall fail to maintain such office or agency
or shall fail to give such notice of the location or of any change in the
location thereof, presentations may be made and notices and demands may be
served at the principal office of the Warrant Agent.

               Any notice pursuant to this Agreement to be given by the Company
or by the registered holder(s) of any Warrant to the Warrant Agent shall be
sufficiently given when and if deposited in the mail, first-class or registered,
postage prepaid, addressed (until another address is filed in writing by the
Warrant Agent with the Company) to the Warrant Agent as follows:

                 The Bank of New York
                 101 Barclay Street, Fl. 8W
                 New York, NY 10286
                 Telecopier No.: (212) 815-5704
                 Attention: Corporate Trust Administration

SECTION 16.         SUPPLEMENTS AND AMENDMENTS.

               The Company and the Warrant Agent may from time to time
supplement or amend this Agreement without the approval of any holders of
Warrants in order to cure any ambiguity or to correct or supplement any
provision contained herein which may be defective or inconsistent with any other
provision herein, or to make any other provisions in regard to matters or
questions arising hereunder which the Company and the Warrant Agent may deem
necessary or desirable and which shall not in any way adversely affect the
interests of the holders of Warrants. Any amendment or supplement to this
Agreement that has an adverse effect on the interests of the holders of Warrants
shall require the written consent of the holders of a majority of the then
outstanding Warrants (excluding Warrants held by the Company or any of its
affiliates). The consent of each holder of Warrants affected shall be required
for any amendment pursuant to which the Exercise Price would be increased or the
number of Warrant Shares purchasable upon exercise of Warrants would be
decreased (other than pursuant to adjustments provided in this Agreement).

SECTION 17.         SUCCESSORS.

               All the covenants and provisions of this Agreement by or for the
benefit of the Company or the Warrant Agent shall bind and inure to the benefit
of their respective successors and assigns hereunder.

                                       35

<PAGE>

SECTION 18.         TERMINATION.

               This Agreement shall terminate at 5:00 p.m., New York City time
on August 1, 2008. Notwithstanding the foregoing, this Agreement will terminate
on any earlier date if all Warrants have been exercised or on the Redemption
Date if the Escrow Corp. Merger has not been consummated. The provisions of
Section 12 shall survive such termination.

SECTION 19.         GOVERNING LAW.

               This Agreement and each Warrant Certificate issued hereunder
shall be deemed to be a contract made under the laws of the State of New York
and for all purposes shall be construed in accordance with the internal laws of
said State.

SECTION 20.         BENEFITS OF THIS AGREEMENT.

               Nothing in this Agreement shall be construed to give to any
person or corporation other than the Company, the Warrant Agent and the
registered holders of Warrants any legal or equitable right, remedy or claim
under this Agreement; but this Agreement shall be for the sole and exclusive
benefit of the Company, the Warrant Agent and the registered holders of
Warrants.

SECTION  21.        COUNTERPARTS.

               This Agreement may be executed in any number of counterparts and
each of such counterparts shall for all purposes be deemed to be an original,
and all such counterparts shall together constitute but one and the same
instrument.

                            [Signature Page Follows]

                                       36

<PAGE>

               IN WITNESS WHEREOF, the parties hereto have caused this Agreement
to be duly executed, as of the day and year first above written.

                                American Tower Corporation


                                By: /s/ Bradley E. Singer
                                   -----------------------------------------
                                    Name: Bradley E. Singer
                                    Title: Chief Financial Officer and Treasurer

                                The Bank of New York, as Warrant Agent


                                By: /s/ Kisha A. Holder
                                   -----------------------------------------
                                    Name: Kisha A. Holder
                                    Title: Assistant Treasurer

                                       37

<PAGE>

                                    EXHIBIT A

                          [Form of Warrant Certificate]

                                     [Face]

               Unit Legend. Each Warrant issued prior to the Separation Date
shall bear the following legend (the "Unit Legend") on the face thereof:

THE WARRANTS EVIDENCED BY THIS CERTIFICATE ARE INITIALLY ISSUED AS PART OF AN
ISSUANCE OF UNITS (THE "UNITS"), EACH OF WHICH CONSISTS OF $1,000 PRINCIPAL
AMOUNT AT MATURITY OF THE 12.25% SENIOR SUBORDINATED DISCOUNT NOTES DUE 2008
(THE "NOTES") OF ESCROW CORP. AND ONE WARRANT TO PURCHASE 14.0953 SHARES, PAR
VALUE $0.01 PER SHARE, OF AMERICAN TOWER CORPORATION.

PRIOR TO THE EARLIEST TO OCCUR OF (I) 180 DAYS AFTER THE CLOSING OF THE
OFFERING, (II) THE DATE ON WHICH A REGISTRATION STATEMENT FOR A REGISTERED
EXCHANGE OFFER WITH RESPECT TO THE NOTES IS DECLARED EFFECTIVE UNDER THE
SECURITIES ACT, (III) THE DATE A SHELF REGISTRATION STATEMENT WITH RESPECT TO
THE WARRANTS IS DECLARED EFFECTIVE UNDER THE SECURITIES ACT, (IV) SUCH DATE AS
CREDIT SUISSE FIRST BOSTON LLC IN ITS SOLE DISCRETION SHALL DETERMINE AND (V) IN
THE EVENT OF A CHANGE OF CONTROL, THE DATE AMERICAN TOWER ESCROW CORPORATION (OR
ITS SUCCESSOR) MAILS THE REQUISITE NOTICE TO THE HOLDERS, THE WARRANTS EVIDENCED
BY THIS CERTIFICATE MAY NOT BE TRANSFERRED OR EXCHANGED SEPARATELY FROM, BUT MAY
BE TRANSFERRED OR EXCHANGED ONLY TOGETHER WITH, THE NOTES.

               Private Placement Legend: Each Warrant issued pursuant to an
exemption from the registration requirements of the Securities Act shall bear
the following legend (the "Private Placement Legend") on the face thereof:

THIS SECURITY (OR ITS PREDECESSOR) AND THE WARRANT SHARES TO BE ISSUED UPON ITS
EXERCISE WAS ORIGINALLY ISSUED IN A TRANSACTION EXEMPT FROM REGISTRATION UNDER
THE UNITED STATES SECURITIES ACT OF 1933 (THE "SECURITIES ACT"). ACCORDINGLY,
THIS SECURITY MAY NOT BE OFFERED, SOLD OR OTHERWISE TRANSFERRED IN THE ABSENCE
OF SUCH REGISTRATION OR AN APPLICABLE EXEMPTION THEREFROM. EACH PURCHASER OF
THIS SECURITY IS HEREBY NOTIFIED THAT THE SELLER OF THIS SECURITY MAY BE RELYING
ON THE EXEMPTION FROM THE PROVISIONS OF SECTION 5 OF THE SECURITIES ACT PROVIDED
BY RULE 144A THEREUNDER.

THE HOLDER OF THIS SECURITY AGREES FOR THE BENEFIT OF THE COMPANY THAT (A) THIS
SECURITY MAY BE OFFERED, RESOLD, PLEDGED OR OTHERWISE TRANSFERRED, ONLY (I) IN
THE UNITED STATES TO A PERSONWHOM THE SELLER REASONABLY BELIEVES IS A QUALIFIED
INSTITUTIONAL BUYER (AS DEFINED IN RULE 144A UNDER THE SECURITIES ACT) IN A
TRANSACTION MEETING THE REQUIREMENTS OF RULE 144A, (II) OUTSIDE THE UNITED
STATES IN AN OFFSHORE TRANSACTION IN ACCORDANCE WITH RULE 904 UNDER THE
SECURITIES ACT, (III) PURSUANT TO AN EXEMPTION FROM REGISTRATION UNDER THE
SECURITIES ACT PROVIDED BY RULE 144 THEREUNDER (IF

                                        1

<PAGE>

AVAILABLE) OR (IV) PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE
SECURITIES ACT, IN EACH OF CASES (I) THROUGH (IV) IN ACCORDANCE WITH ANY
APPLICABLE SECURITIES LAWS OF ANY STATE OF THE UNITED STATES, AND (B) THE
HOLDERWILL, AND EACH SUBSEQUENT HOLDER IS REQUIRED TO, NOTIFY ANY PURCHASER OF
THIS WARRANT FROM IT OF THE RESALE RESTRICTIONS REFERRED TO IN (A) ABOVE.

THE HOLDER OF THIS SECURITY AGREES NOT TO ENGAGE IN HEDGING TRANSACTIONS UNLESS
IN COMPLIANCE WITH THE SECURITIES ACT AND (4) AGREES THAT IT WILL DELIVER TO
EACH PERSON TO WHOM THIS SECURITY OR AN INTEREST HEREIN IS TRANSFERRED A NOTICE
SUBSTANTIALLY TO THE EFFECT OF THIS LEGEND.

AS USED HEREIN, THE TERMS "OFFSHORE TRANSACTION" AND "UNITED STATES" HAVE THE
MEANINGS GIVEN TO THEM BY RULE 902 OF REGULATION S UNDER THE SECURITIES ACT. THE
WARRANT AGREEMENT CONTAINS A PROVISION REQUIRING THE WARRANT AGENT TO REFUSE TO
REGISTER ANY TRANSFER OF THIS SECURITY IN VIOLATION OF THE FOREGOING.

               Global Warrant Legend. Each Global Warrant shall bear the
following legend (the "Global Warrant Legend") on the face thereof:

THIS GLOBAL WARRANT IS HELD BY THE DEPOSITARY (AS DEFINED IN THE WARRANT
AGREEMENT GOVERNING THIS WARRANT) OR ITS NOMINEE IN CUSTODY FOR THE BENEFIT OF
THE BENEFICIAL OWNERS HEREOF, AND IS NOT TRANSFERABLE TO ANY PERSON UNDER ANY
CIRCUMSTANCES EXCEPT THAT (I) THE WARRANT AGENT MAY MAKE SUCH NOTATIONS HEREON
AS MAY BE REQUIRED PURSUANT TO SECTION 3.5 OF THE WARRANT AGREEMENT, (II) THIS
GLOBAL WARRANT MAY BE EXCHANGED IN WHOLE BUT NOT IN PART PURSUANT TO SECTION
3.5(A) OF THE WARRANT AGREEMENT, (III) THIS GLOBAL WARRANT MAY BE DELIVERED TO
THE WARRANT AGENT FOR CANCELLATION PURSUANT TO SECTION 3.8 OF THE WARRANT
AGREEMENT AND (IV) THIS GLOBAL WARRANT MAY BE TRANSFERRED TO A SUCCESSOR
DEPOSITARY WITH THE PRIOR WRITTEN CONSENT OF AMERICAN TOWER CORPORATION (THE
"COMPANY").

               Regulation S Legend. Each Warrant that is a Registrable Security
and issued pursuant to Regulation S shall bear the following legend (the
"Regulation S Legend") on the face thereof:

THIS WARRANT AND THE SECURITIES TO BE ISSUED UPON ITS EXERCISE HAVE NOT BEEN
REGISTERED UNDER THE SECURITIES ACT AND THE WARRANT MAY NOT BE EXERCISED BY OR
ON BEHALF OF ANY U.S. PERSON UNLESS REGISTERED UNDER THE U.S. SECURITIES ACT OF
1933, AS AMENDED (THE "SECURITIES ACT") OR AN EXEMPTION FROM SUCH REGISTRATION
IS AVAILABLE. IN ORDER TO EXERCISE THIS WARRANT, THE HOLDER MUST FURNISH TO THE
COMPANY AND THE WARRANT AGENT EITHER (A) A WRITTEN CERTIFICATION THAT IT IS NOT
A U.S. PERSON AND THE WARRANT IS NOT BEING EXERCISED ON BEHALF OF A U.S. PERSON
OR (B) A WRITTEN OPINION OF COUNSEL TO THE EFFECT THAT THE SECURITIES DELIVERED
UPON EXERCISE OF THE WARRANT HAVE BEEN REGISTERED UNDER THE SECURITIES ACT OR
THAT THE DELIVERY OF SUCH SECURITIES IS EXEMPT FROM THE REGISTRATION
REQUIREMENTS

                                        2

<PAGE>

OF THE SECURITIES ACT. TERMS IN THIS LEGEND HAVE THE MEANINGS GIVEN TO THEM BY
REGULATION S UNDER THE SECURITIES ACT.

                                        3

<PAGE>

No. ___________    ___Warrants
CUSIP No. ________

                               Warrant Certificate

                           AMERICAN TOWER CORPORATION

               This Warrant Certificate certifies that Cede & Co., or its
registered assigns, is the registered holder of Warrants expiring August 1, 2008
(the "Warrants") to purchase Class A Common Stock, par value $0.01 (the "Common
Stock"), of American Tower Corporation, a Delaware corporation. Each Warrant
entitles the registered holder upon exercise at any time on or after the opening
of business on January 29, 2006 until 5:00 p.m., New York City time before or on
August 1, 2008 (the "Exercise Period), to receive from the Company 14.0953 fully
paid and nonassessable shares of Common Stock (the "Warrant Shares") at the
initial exercise price (the "Exercise Price") of $0.01 per share payable upon
surrender of this Warrant Certificate and payment of the Exercise Price at the
office or agency of the Warrant Agent, but only subject to the conditions set
forth herein and in the Warrant Agreement referred to on the reverse hereof. The
Exercise Price and number of Warrant Shares issuable upon exercise of the
Warrants are subject to adjustment upon the occurrence of certain events set
forth in the Warrant Agreement. Notwithstanding the foregoing, if the Escrow
Corp. Merger has not been consummated and the Notes have been mandatorily
redeemed pursuant to Section 3.08 of the Indenture (the "Redemption Date"), each
Warrant shall become void and all rights thereunder and all rights in respect
thereof under this Agreement shall cease as of the Redemption Date.

               No Warrant may be exercised after 5:00 p.m., New York City time
on August 1, 2008, and to the extent not exercised by such time such Warrants
shall become void.

               Reference is hereby made to the further provisions of this
Warrant Certificate set forth on the reverse hereof and such further provisions
shall for all purposes have the same effect as though fully set forth at this
place.

               This Warrant Certificate shall not be valid unless countersigned
by the Warrant Agent, as such term is used in the Warrant Agreement.

               This Warrant Certificate shall be governed by and construed in
accordance with the internal laws of the State of New York.

                                        1

<PAGE>

                  IN WITNESS WHEREOF, the Company has caused this Warrant
Certificate to be signed below.

Dated: January 29, 2003

                           American Tower Corporation


                           By:
                               ----------------------------------------------
                               Name:  Bradley E. Singer
                               Title: Chief Financial Officer and Treasurer

Countersigned:

The Bank of New York
as Warrant Agent


By:
    --------------------------
    Name:  Kisha A. Holder
    Title: Assistant Treasurer

                                        2

<PAGE>

                        [Reverse of Warrant Certificate]

               The Warrants evidenced by this Warrant Certificate are part of a
duly authorized issue of Warrants expiring at 5:00 p.m. New York City time on
August 1, 2008 entitling the holder upon exercise to receive shares of Class A
Common Stock, and are issued or to be issued pursuant to a Warrant Agreement
dated as of January 29, 2003 (the "Warrant Agreement"), duly executed and
delivered by the Company to The Bank of New York, as warrant agent (the "Warrant
Agent"), which Warrant Agreement is hereby incorporated by reference in and made
a part of this instrument and is hereby referred to for a description of the
rights, limitation of rights, obligations, duties and immunities thereunder of
the Warrant Agent, the Company and the holders (the words "holders" or "holder"
meaning the registered holders or registered holder) of the Warrants. A copy of
the Warrant Agreement may be obtained by the holder hereof upon written request
to the Company.

               Warrants may be exercised at any time on or after the opening of
business on January 29, 2006 and on or before 5:00 p.m. New York City time on
August 1, 2008; provided that holders shall be able to exercise their Warrants
only if a registration statement relating to the Warrants Shares is then in
effect, or the exercise of such Warrants is exempt from the registration
requirements of the Securities Act of 1933, as amended (the "Securities Act"),
and such securities are qualified for sale or exempt from qualification under
the applicable securities laws of the states in which the various holders of the
Warrants or other persons to whom it is proposed that the Warrant Shares be
issued on exercise of the Warrants reside. In order to exercise all or any of
the Warrants represented by this Warrant Certificate, the holder must deliver to
the Warrant Agent at its New York corporate trust office set forth in Section 15
of the Warrant Agreement this Warrant Certificate and the form of election to
purchase on the reverse hereof duly filled in and signed, which signature shall
be medallion guaranteed by an institution which is a member of a Securities
Transfer Association recognized signature guarantee program, and upon payment to
the Warrant Agent for the account of the Company of the Exercise Price, as
adjusted as provided in the Warrant Agreement, for the number of Warrant Shares
in respect of which such Warrants are then exercised. No adjustment shall be
made for any dividends on any Common Stock issuable upon exercise of this
Warrant. Notwithstanding the foregoing, if the Escrow Corp. Merger has not been
consummated and the Notes have been mandatorily redeemed pursuant to Section
3.08 of the Indenture (the "Redemption Date"), each Warrant shall become void
and all rights thereunder and all rights in respect thereof under this Agreement
shall cease as of the Redemption Date.

               The Warrant Agreement provides that upon the occurrence of
certain events the Exercise Price set forth on the face hereof may, subject to
certain conditions, be adjusted. If the Exercise Price is adjusted, the Warrant
Agreement provides that the number of shares of Common Stock issuable upon the
exercise of each Warrant shall be adjusted. No fractions of a share of Common
Stock will be issued upon the exercise of any Warrant, but the Company will pay
the cash value thereof determined as provided in the Warrant Agreement.

                  The Company has agreed pursuant to a Warrant Registration
Rights Agreement dated as of January 29, 2003 (the "Warrant Registration Rights
Agreement") to file within 90 days after the issuance of the Warrants and use
its reasonable best efforts to make effective, subject to certain exceptions
detailed in the Warrant Registration Rights Agreement, on or before 180 days
after such date a shelf registration statement covering the resale of the
Warrants, the issuance by American Tower Corporation's common stock upon the
exercise of the warrants resold pursuant to such registration statement and the
resale of the Warrant Shares by the holder thereof on the appropriate form under
the Securities Act, and to use its reasonable best efforts (subject to certain
"black-out" periods not to exceed 60 days in any calendar year subject to
extension for 30 days in certain circumstances) to keep such

                                       A-1

<PAGE>

registration statement continuously effective under the Securities Act, subject
to certain exceptions, until two years following the Closing Date.

               Warrant Certificates, when surrendered at the office of the
Warrant Agent by the registered holder thereof in person or by legal
representative or attorney duly authorized in writing, may be exchanged, in the
manner and subject to the limitations provided in the Warrant Agreement, but
without payment of any service charge, for another Warrant Certificate or
Warrant Certificates of like tenor evidencing in the aggregate a like number of
Warrants.

               Upon due presentation for registration of transfer of this
Warrant Certificate at the office of the Warrant Agent a new Warrant Certificate
or Warrant Certificates of like tenor and evidencing in the aggregate a like
number of Warrants shall be issued to the transferee(s) in exchange for this
Warrant Certificate, subject to the limitations provided in the Warrant
Agreement, without charge except for any tax or other governmental charge
imposed in connection therewith.

               The Company and the Warrant Agent may deem and treat the
registered holder(s) thereof as the absolute owner(s) of this Warrant
Certificate (notwithstanding any notation of ownership or other writing hereon
made by anyone), for the purpose of any exercise hereof, of any distribution to
the holder(s) hereof, and for all other purposes, and neither the Company nor
the Warrant Agent shall be affected by any notice to the contrary. Neither the
Warrants nor this Warrant Certificate entitles any holder hereof to any rights
of a stockholder of the Company.

                                       A-2

<PAGE>

                         [Form of Election to Purchase]

                    (To Be Executed Upon Exercise Of Warrant)

               The undersigned hereby irrevocably elects to exercise the right,
represented by this Warrant Certificate, to receive _____________ shares of
Class A Common Stock and herewith tenders payment for such shares to the order
of AMERICAN TOWER CORPORATION in the amount of $__________ in accordance with
the terms hereof. The undersigned requests that a certificate for such shares be
registered in the name of _______________, whose address is __________________
and that such shares be delivered to ___________, whose address is
____________________________. If said number of shares is less than all of the
shares of Common Stock purchasable hereunder, the undersigned requests that a
new Warrant Certificate representing the remaining balance of such shares be
registered in the name of ______________________, whose address is
____________________, and that such Warrant Certificate be delivered to whose
address is ____________________.


                                        ----------------------------------------
                                        Signature

Date:

                                        ----------------------------------------
                                        Signature Guaranteed

Signatures must be guaranteed by an "eligible guarantor institution" meeting the
requirements of the Warrant Agent, which requirements include membership or
participation in the Security Transfer Agent Medallion Program ("STAMP") or such
other "signature guarantee program" as may be determined by the Warrant Agent in
addition to, or in substitution for, STAMP, all in accordance with the
Securities Exchange Act of 1934, as amended.

                                       A-3

<PAGE>

              SCHEDULE OF EXCHANGES OF INTERESTS OF GLOBAL WARRANTS

The following exchanges of a part of this Global Warrant have been made:

<TABLE>
<CAPTION>
                                                                       Number of Warrants
                      Amount of decrease                                 in this Global
                         in Number of        Amount of increase in      Warrant following        Signature of
                       warrants in this      Number of Warrants in       such decrease or     authorized officer
Date of Exchange        Global Warrant        this Global Warrant            increase          of Warrant Agent
------------------   --------------------   -----------------------   --------------------   --------------------
<S>                       <C>                    <C>                     <C>                    <C>

</TABLE>

                                       A-4

<PAGE>

                                    EXHIBIT B

                         FORM OF CERTIFICATE OF TRANSFER

American Tower Corporation
116 Huntington Avenue, 11th Floor
Boston, MA 02116
Attention: [________]

The Bank of New York
[_______________]
[_______________]
Attention: [__________]

           Re: Warrants

               Reference is hereby made to the Warrant Agreement, dated as of
January 29, 2003 (the "Warrant Agreement"), between American Tower Corporation,
as issuer (the "Company"), and The Bank of New York, as warrant agent.
Capitalized terms used but not defined herein shall have the meanings given to
them in the Warrant Agreement.

               ___________________, (the "Transferor") owns and proposes to
transfer the Warrant[s] or interest in such Warrant[s] specified in Annex A
hereto, in the principal amount at maturity of $___________ in such Warrant[s]
or interests (the "Transfer"), to ___________________________ (the
"Transferee"), as further specified in Annex A hereto. In connection with the
Transfer, the Transferor hereby certifies that:

                             [CHECK ALL THAT APPLY]

               1.   [ ] Check if Transferee will take delivery of a beneficial
interest in the 144A Global Warrant or a Definitive Warrant Pursuant to Rule
144A. The Transfer is being effected pursuant to and in accordance with Rule
144A under the United States Securities Act of 1933, as amended (the "Securities
Act"), and, accordingly, the Transferor hereby further certifies that the
beneficial interest or Definitive Warrant is being transferred to a Person that
the Transferor reasonably believed and believes is purchasing the beneficial
interest or Definitive Warrant for its own account, or for one or more accounts
with respect to which such Person exercises sole investment discretion, and such
Person and each such account is a "qualified institutional buyer" within the
meaning of Rule 144A in a transaction meeting the requirements of Rule 144A and
such Transfer is in compliance with any applicable blue sky securities laws of
any state of the United States. Upon consummation of the proposed Transfer in
accordance with the terms of the Warrant Agreement, the transferred beneficial
interest or Definitive Warrant will be subject to the restrictions on transfer
enumerated in the Private Placement Legend printed on the 144A Global Warrant
and/or the Definitive Warrant and in the Warrant Agreement and the Securities
Act.

               2.   [ ] Check if Transferee will take delivery of a beneficial
interest in the Regulation S Global Warrant or a Definitive Warrant pursuant to
Regulation S. The Transfer is being effected pursuant to and in accordance with
Rule 903 or Rule 904 under the Securities Act and, accordingly, the Transferor
hereby further certifies that (i) the Transfer is not being made to a person in
the United States and (x) at the time the buy order was originated, the
Transferee was outside the United

                                       B-1

<PAGE>

States or such Transferor and any Person acting on its behalf reasonably
believed and believes that the Transferee was outside the United States or (y)
the transaction was executed in, on or through the facilities of a designated
offshore securities market and neither such Transferor nor any Person acting on
its behalf knows that the transaction was prearranged with a buyer in the United
States, (ii) no directed selling efforts have been made in contravention of the
requirements of Rule 903(b) or Rule 904(b) of Regulation S under the Securities
Act, (iii) the transaction is not part of a plan or scheme to evade the
registration requirements of the Securities Act and (iv) if the proposed
transfer is being made prior to the expiration of the Restricted Period, the
transfer is not being made to a U.S. Person or for the account or benefit of a
U.S. Person (other than an Initial Purchaser). Upon consummation of the proposed
transfer in accordance with the terms of the Warrant Agreement, the transferred
beneficial interest or Definitive Warrant will be subject to the restrictions on
Transfer enumerated in the Private Placement Legend printed on the Regulation S
Global Warrant and/or the Definitive Warrant and in the Warrant Agreement and
the Securities Act.

               3.   [ ] Check and complete if Transferee will take delivery of a
beneficial interest in the IAI Global Warrant or a Definitive Warrant pursuant
to any provision of the Securities Act other than Rule 144A or Regulation S. The
Transfer is being effected in compliance with the transfer restrictions
applicable to beneficial interests in Restricted Global Warrants and Restricted
Definitive Warrants and pursuant to and in accordance with the Securities Act
and any applicable blue sky securities laws of any state of the United States,
and accordingly the Transferor hereby further certifies that (check one):

        (a) [ ] such Transfer is being effected pursuant to and in accordance
        with Rule 144 under the Securities Act;

                                       or

        (b) [ ] such Transfer is being effected to the Company or a subsidiary
        thereof;

                                       or

        (c) [ ] such Transfer is being effected pursuant to an effective
        registration statement under the Securities Act and in compliance with
        the prospectus delivery requirements of the Securities Act;

                                       or

        (d) [ ] such Transfer is being effected to an Institutional Accredited
        Investor and pursuant to an exemption from the registration requirements
        of the Securities Act other than Rule 144A, Rule 144 or Rule 904, and
        the Transferor hereby further certifies that it has not engaged in any
        general solicitation within the meaning of Regulation D under the
        Securities Act and the Transfer complies with the transfer restrictions
        applicable to beneficial interests in a Restricted Global Warrant or
        Restricted Definitive Warrants and the requirements of the exemption
        claimed, which certification is supported by (1) a certificate executed
        by the Transferee in the form of Exhibit D to the Warrant Agreement and
        (2) if the Company requests, an Opinion of Counsel provided by the
        Transferor or the Transferee (a copy of which the Transferor has
        attached to this certification), to the effect that such Transfer is in
        compliance with the Securities Act. Upon consummation of the proposed
        transfer in accordance with the terms of the Warrant Agreement, the
        transferred beneficial interest or Definitive Warrant will be subject to
        the restrictions on transfer enumerated in the Private Placement Legend
        printed on the IAI Global Warrant and/or the Definitive Warrants and in
        the Warrant Agreement and the Securities Act.

                                       B-2

<PAGE>

               4.   [ ] Check if Transferee will take delivery of a beneficial
interest in an Unrestricted Global Warrant or of an Unrestricted Definitive
Warrant.

        (a) [ ] Check if Transfer is pursuant to Rule 144. (i) The Transfer is
        being effected pursuant to and in accordance with Rule 144 under the
        Securities Act and in compliance with the transfer restrictions
        contained in the Warrant Agreement and any applicable blue sky
        securities laws of any state of the United States and (ii) the
        restrictions on transfer contained in the Warrant Agreement and the
        Private Placement Legend are not required in order to maintain
        compliance with the Securities Act. Upon consummation of the proposed
        Transfer in accordance with the terms of the Warrant Agreement, the
        transferred beneficial interest or Definitive Warrant will no longer be
        subject to the restrictions on transfer enumerated in the Private
        Placement Legend printed on the Restricted Global Warrants, on
        Restricted Definitive Warrants and in the Warrant Agreement.

        (b) [ ] Check if Transfer is Pursuant to Regulation S. (i) The Transfer
        is being effected pursuant to and in accordance with Rule 903 or Rule
        904 under the Securities Act and in compliance with the transfer
        restrictions contained in the Warrant Agreement and any applicable blue
        sky securities laws of any state of the United States and (ii) the
        restrictions on transfer contained in the Warrant Agreement and the
        Private Placement Legend are not required in order to maintain
        compliance with the Securities Act. Upon consummation of the proposed
        Transfer in accordance with the terms of the Warrant Agreement, the
        transferred beneficial interest or Definitive Warrant will no longer be
        subject to the restrictions on transfer enumerated in the Private
        Placement Legend printed on the Restricted Global Warrants, on
        Restricted Definitive Warrants and in the Warrant Agreement.

        (c) [ ] Check if Transfer is Pursuant to Other Exemption. (i) The
        Transfer is being effected pursuant to and in compliance with an
        exemption from the registration requirements of the Securities Act other
        than Rule 144, Rule 903 or Rule 904 and in compliance with the transfer
        restrictions contained in the Warrant Agreement and any applicable blue
        sky securities laws of any State of the United States and (ii) the
        restrictions on transfer contained in the Warrant Agreement and the
        Private Placement Legend are not required in order to maintain
        compliance with the Securities Act. Upon consummation of the proposed
        Transfer in accordance with the terms of the Warrant Agreement, the
        transferred beneficial interest or Definitive Warrant will not be
        subject to the restrictions on transfer enumerated in the Private
        Placement Legend printed on the Restricted Global Warrants or Restricted
        Definitive Warrants and in the Warrant Agreement.

               This certificate and the statements contained herein are made for
your benefit and the benefit of the Company.

                                          --------------------------------------
                                                [Insert Name of Transferor]

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

Dated:
       -------------------------------------

                                       B-3

<PAGE>

                       ANNEX A TO CERTIFICATE OF TRANSFER

1. The Transferor owns and proposes to transfer the following:

                            [CHECK ONE OF (a) OR (b)]

          (a) [ ] a beneficial interest in the:

              (i)   [ ] 144A Global Warrant, or

              (ii)  [ ] Regulation S Global Warrant, or

              (iii) [ ] IAI Global Warrant; or

          (b) [ ] a Restricted Definitive Warrant.

2. After the Transfer the Transferee will hold:

                                   [CHECK ONE]

          (a) [ ] a beneficial interest in the:

              (i)   [ ] 144A Global Warrant, or

              (ii)  [ ] Regulation S Global Warrant, or

              (iii) [ ] IAI Global Warrant, or

              (iv)  [ ] Unrestricted Global Warrant; or

          (b) [ ] a Restricted Definitive Warrant; or

          (c) [ ] an Unrestricted Definitive Warrant,

          in accordance with the terms of the Warrant Agreement.

                                       B-4

<PAGE>

                                    EXHIBIT C
                         FORM OF CERTIFICATE OF EXCHANGE

American Tower Corporation
116 Huntington Avenue, 11th Floor
Boston, MA 02116
Attention: [________]

The Bank of New York
[_____________]

[_____________]
Attention: [__________]


         Re:  Warrants

                              (CUSIP ____________)

               Reference is hereby made to the Warrant Agreement, dated as of
January 29, 2003 (the "Warrant Agreement"), between American Tower Corporation,
as issuer (the "Company"), and The Bank of New York, as warrant agent.
Capitalized terms used but not defined herein shall have the meanings given to
them in the Warrant Agreement.

               __________________________, (the "Owner") owns and proposes to
exchange the Warrant[s] or interest in such Warrant[s] specified herein, in the
amount of $____________ in such Warrant[s] or interests (the "Exchange"). In
connection with the Exchange, the Owner hereby certifies that:

               1. Exchange of Restricted Definitive Warrants or Beneficial
Interests in a Restricted Global Warrant for Unrestricted Definitive Warrants or
Beneficial Interests in an Unrestricted Global Warrant

        (a) [ ] Check if Exchange is from beneficial interest in a Restricted
        Global Warrant to beneficial interest in an Unrestricted Global Warrant.
        In connection with the Exchange of the Owner's beneficial interest in a
        Restricted Global Warrant for a beneficial interest in an Unrestricted
        Global Warrant in an equal principal amount, the Owner hereby certifies
        (i) the beneficial interest is being acquired for the Owner's own
        account without transfer, (ii) such Exchange has been effected in
        compliance with the transfer restrictions applicable to the Global
        Warrants and pursuant to and in accordance with the United States
        Securities Act of 1933, as amended (the "Securities Act"), (iii) the
        restrictions on transfer contained in the Warrant Agreement and the
        Private Placement Legend are not required in order to maintain
        compliance with the Securities Act and (iv) the beneficial interest in
        an Unrestricted Global Warrant is being acquired in compliance with any
        applicable blue sky securities laws of any state of the United States.

        (b) [ ] Check if Exchange is from beneficial interest in a Restricted
        Global Warrant to Unrestricted Definitive Warrant. In connection with
        the Exchange of the Owner's beneficial interest in a Restricted Global
        Warrant for an Unrestricted Definitive Warrant, the Owner hereby
        certifies (i) the Definitive Warrant is being acquired for the Owner's
        own account without transfer,

                                       C-1

<PAGE>

        (ii) such Exchange has been effected in compliance with the transfer
        restrictions applicable to the Restricted Global Warrants and pursuant
        to and in accordance with the Securities Act, (iii) the restrictions on
        transfer contained in the Warrant Agreement and the Private Placement
        Legend are not required in order to maintain compliance with the
        Securities Act and (iv) the Definitive Warrant is being acquired in
        compliance with any applicable blue sky securities laws of any state of
        the United States.

        (c) [ ] Check if Exchange is from Restricted Definitive Warrant to
        beneficial interest in an Unrestricted Global Warrant. In connection
        with the Owner's Exchange of a Restricted Definitive Warrant for a
        beneficial interest in an Unrestricted Global Warrant, the Owner hereby
        certifies (i) the beneficial interest is being acquired for the Owner's
        own account without transfer, (ii) such Exchange has been effected in
        compliance with the transfer restrictions applicable to Restricted
        Definitive Warrants and pursuant to and in accordance with the
        Securities Act, (iii) the restrictions on transfer contained in the
        Warrant Agreement and the Private Placement Legend are not required in
        order to maintain compliance with the Securities Act and (iv) the
        beneficial interest is being acquired in compliance with any applicable
        blue sky securities laws of any state of the United States.

        (d) [ ] Check if Exchange is from Restricted Definitive Warrant to
        Unrestricted Definitive Warrant. In connection with the Owner's Exchange
        of a Restricted Definitive Warrant for an Unrestricted Definitive
        Warrant, the Owner hereby certifies (i) the Unrestricted Definitive
        Warrant is being acquired for the Owner's own account without transfer,
        (ii) such Exchange has been effected in compliance with the transfer
        restrictions applicable to Restricted Definitive Warrants and pursuant
        to and in accordance with the Securities Act, (iii) the restrictions on
        transfer contained in the Warrant Agreement and the Private Placement
        Legend are not required in order to maintain compliance with the
        Securities Act and (iv) the Unrestricted Definitive Warrant is being
        acquired in compliance with any applicable blue sky securities laws of
        any state of the United States.

               2.   Exchange of Restricted Definitive Warrants or Beneficial
Interests in Restricted Global Warrants for Restricted Definitive Warrants or
Beneficial Interests in Restricted Global Warrants

        (a) [ ] Check if Exchange is from beneficial interest in a Restricted
        Global Warrant to Restricted Definitive Warrant. In connection with the
        Exchange of the Owner's beneficial interest in a Restricted Global
        Warrant for a Restricted Definitive Warrant in a number equal to the
        number of beneficial interests exchanged, the Owner hereby certifies
        that the Restricted Definitive Warrant is being acquired for the Owner's
        own account without transfer. Upon consummation of the proposed Exchange
        in accordance with the terms of the Warrant Agreement, the Restricted
        Definitive Warrant issued will continue to be subject to the
        restrictions on transfer enumerated in the Private Placement Legend
        printed on the Restricted Definitive Warrant and in the Warrant
        Agreement and the Securities Act.

        (b) Check if Exchange is from Restricted Definitive Warrant to
        beneficial interest in a Restricted Global Warrant. In connection with
        the Exchange of the Owner's Restricted Definitive Warrant for a
        beneficial interest in the [CHECK ONE] [ ] 144A Global Warrant, [ ]
        Regulation S Global Warrant, [ ] IAI Global Warrant in a number equal to
        the number of beneficial interests exchanged, the Owner hereby certifies
        (i) the beneficial interest is being acquired for the Owner's own
        account without transfer and (ii) such Exchange has been effected in
        compliance with the transfer restrictions applicable to the Restricted
        Global Warrants and pursuant to and in

                                       C-2

<PAGE>

        accordance with the Securities Act, and in compliance with any
        applicable blue sky securities laws of any state of the United States.
        Upon consummation of the proposed Exchange in accordance with the terms
        of the Warrant Agreement, the beneficial interest issued will be subject
        to the restrictions on transfer enumerated in the Private Placement
        Legend printed on the relevant Restricted Global Warrant and in the
        Warrant Agreement and the Securities Act.

               This certificate and the statements contained herein are made for
your benefit and the benefit of the Company.

                                          --------------------------------------
                                                [Insert Name of Transferor]

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

Dated:
       -------------------------------------

                                       C-3

<PAGE>

                                    EXHIBIT D
                            FORM OF CERTIFICATE FROM
                   ACQUIRING INSTITUTIONAL ACCREDITED INVESTOR

American Tower Corporation
116 Huntington Avenue, 11th Floor
Boston, MA 02116
Attention: [________]

The Bank of New York
[_______________]
[_______________]
Attention: [__________]

         Re: Warrants

               Reference is hereby made to the Warrant Agreement, dated as of
January 29, 2003 (the "Warrant Agreement"), between American Tower Corporation,
as issuer (the "Company"), and The Bank of New York, as warrant agent.
Capitalized terms used but not defined herein shall have the meanings given to
them in the Warrant Agreement.

               In connection with our proposed purchase of $____________ amount
of:

     (a) [ ] a beneficial interest in a Global Warrant, or

     (b) [ ] a Definitive Warrant,

               we confirm that:

               1.   We understand that any subsequent transfer of the Warrants
or any interest therein is subject to certain restrictions and conditions set
forth in the Warrant Agreement and the undersigned agrees to be bound by, and
not to resell, pledge or otherwise transfer the Warrants or any interest therein
except in compliance with, such restrictions and conditions and the United
States Securities Act of 1933, as amended (the "Securities Act").

               2.   We understand that the offer and sale of the Warrants have
not been registered under the Securities Act, and that the Warrants and any
interest therein may not be offered or sold except as permitted in the following
sentence. We agree, on our own behalf and on behalf of any accounts for which we
are acting as hereinafter stated, that if we should sell the Warrants or any
interest therein, we will do so only (A) to the Company or any subsidiary
thereof, (B) in accordance with Rule 144A under the Securities Act to a
"qualified institutional buyer" (as defined therein), (C) to an institutional
"accredited investor" (as defined below) that, prior to such transfer, furnishes
(or has furnished on its behalf by a U.S. broker-dealer) to you and to the
Company a signed letter substantially in the form of this letter and, if
requested by the Company, an Opinion of Counsel in form reasonably acceptable to
the Company to the effect that such transfer is in compliance with the
Securities Act, (D) outside the United States in accordance with Rule 904 of
Regulation S under the Securities Act, (E) pursuant to the provisions of Rule
144(k) under the Securities Act or (F) pursuant to an effective registration
statement under the Securities Act, and we further agree to provide to any
person purchasing the Definitive Warrant

                                       D-1

<PAGE>

or beneficial interest in a Global Warrant from us in a transaction meeting the
requirements of clauses (A) through (E) of this paragraph a notice advising such
purchaser that resales thereof are restricted as stated herein.

               3.   We understand that, on any proposed resale of the Warrants
or beneficial interest therein, we will be required to furnish to you and the
Company such certifications, legal opinions and other information as you and the
Company may reasonably require to confirm that the proposed sale complies with
the foregoing restrictions. We further understand that the Warrants purchased by
us will bear a legend to the foregoing effect.

               4.   We are an institutional "accredited investor" (as defined in
Rule 501(a)(1), (2), (3) or (7) of Regulation D under the Securities Act) and
have such knowledge and experience in financial and business matters as to be
capable of evaluating the merits and risks of our investment in the Warrants,
and we and any accounts for which we are acting are each able to bear the
economic risk of our or its investment.

               5.   We are acquiring the Warrants or beneficial interest therein
purchased by us for our own account or for one or more accounts (each of which
is an institutional "accredited investor") as to each of which we exercise sole
investment discretion.

               We agree not to engage in any hedging transactions with regard to
the Warrants unless such hedging transactions are in compliance with the
Securities Act.

               You and the Company are entitled to rely upon this letter and are
irrevocably authorized to produce this letter or a copy hereof to any interested
party in any administrative or legal proceedings or official inquiry with
respect to the matters covered hereby.

                                          --------------------------------------
                                                [Insert Name of Transferor]

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

Dated:
       -------------------------------------

                                       D-2

<PAGE>

                                    EXHIBIT E

                  FORM OF WARRANT REGISTRATION RIGHTS AGREEMENT

                                       E-1