Document:

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                      SIXTH AMENDMENT TO CREDIT AGREEMENT

         THIS SIXTH AMENDMENT TO CREDIT AGREEMENT AND WAIVER (this "Amendment")
is made and entered into as of the day of February, 2000, by and between
EDUTREK INTERNATIONAL, INC., a Georgia corporation ("Borrower"), the
undersigned Guarantors party hereto (the "Guarantors"; Borrower and the
Guarantors are individually a "Credit Party" and collectively the "Credit
Parties") and FIRST UNION NATIONAL BANK ("Lender").

                                  WITNESSETH:

         WHEREAS, Borrower and Lender are a party to that certain Credit
Agreement, dated as of March 25, 1999, as amended by a First Amendment to
Credit Agreement dated May 27, 1999, by a Second Amendment to Credit Agreement
and Waiver dated August 16, 1999, by a Third Amendment to Credit Agreement
dated August 27, 1999, by a Fourth Amendment to Credit Agreement and Waiver
dated November 11, 1999 and by a Fifth Amendment to Credit Agreement and Waiver
dated December 23, 1999 (as amended, the "Credit Agreement"), pursuant to which
Lender made available to Borrower a $10,000,000 revolving line of credit
pursuant to the Facility A Commitment and a line of credit providing a maximum
availability of $2,299,360 pursuant to the Facility B Commitment; and

         WHEREAS, Borrower has requested that the Lender increase the amount of
the Facility B Commitment, extend the maturity of the Facility B Loans, and
make certain other modifications to the terms and conditions in the Credit
Agreement; and

         WHEREAS, Lender is willing to agree to such amendments and
modifications only if Borrower agrees that the Credit Agreement be further
amended as set forth herein;

         NOW, THEREFORE, for and in consideration of the foregoing premises,
the mutual promises, covenants and agreements contained herein, and other good
and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto hereby agree as follows:

         1.       DEFINITIONS. All capitalized terms used herein and not
expressly defined herein shall have the same respective meanings given to such
terms in the Credit Agreement.

         2.       AMENDMENTS. Subject to the conditions contained herein, the
Credit Agreement is hereby amended as follows:

                  2.1.     NEW DEFINITIONS. Section 1.1 of the Credit Agreement
is hereby amended by adding thereto in appropriate alphabetical order the
following new definitions:

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                           "Sixth Amendment" shall mean that certain Sixth
                  Amendment to Credit Agreement, dated as of February , 2000,
                  between Borrower and Lender.

                           "Sixth Amendment Effective Date" shall mean that
                  date on which all of the conditions precedent set forth in
                  Section 4 of the Sixth Amendment have been satisfied and the
                  Sixth Amendment has become effective.

                  2.2.     EXISTING DEFINITIONS. Section 1.1 of the Credit
Agreement is hereby further amended by deleting the definitions of "Facility B
Commitment," and "Facility B Termination Date" and by substituting in lieu
thereof the following new definitions of such terms:

                           "Facility B Commitment" means the obligation of the
                  Lender to make Loans to the Borrower pursuant to Section
                  2.1(b) hereof in an aggregate principal amount at any time
                  outstanding not to exceed Four Million Three Hundred Fifty
                  Thousand Dollars ($4,350,000) as such amount is reduced
                  pursuant to Section 2.5(c) hereof.

                           "Facility B Termination Date" means the earliest of
                  (a) September 30, 2000, (b) the date of termination by the
                  Borrower pursuant to Section 2.5(a), (c) the Termination
                  Date; and (d) the date of termination by the Lender pursuant
                  to Section 11.2(a).

                  2.3.     COMMITMENT REDUCTION. The Credit Agreement is hereby
further amended by deleting Section 2.5 thereof in its entirety, and
substituting in lieu thereof the following new Section 2.5 to read as follows:

                  SECTION 2.5 Permanent Reduction of the Commitment.

                           (a)      The Borrower shall have the right at any
                  time and from time to time, upon at least five (5) Business
                  Days prior written notice to the Lender, to permanently
                  reduce, in whole at any time or in part from time to time,
                  without premium or penalty, either the Facility A Commitment
                  or the Facility B Commitment in an aggregate principal amount
                  not less than $100,000 or any whole multiple of $10,000 in
                  excess thereof.

                           (b)      The Facility A Commitment shall (i)
                  immediately upon any demand for payment made by Lender
                  pursuant to Section 2.3(a) hereof, reduce to the amount of
                  the outstanding principal balance of the Facility A Loans and
                  (ii) thirty (30) days after such demand for payment, reduce
                  to zero.

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                           (c)      The Facility B Commitment shall (i) on July
                  1, 2000, reduce to $3,500,000 and (ii) on the Facility B
                  Termination Date, reduce to zero.

                           (d)      Each permanent reduction permitted or
                  required pursuant to this Section 2.5 shall be accompanied by
                  a payment of principal sufficient to reduce the sum of the
                  aggregate outstanding Facility A Loans plus the outstanding
                  L/C Obligations after such reduction to the Facility A
                  Commitment as so reduced and/or to reduce the sum of the
                  aggregate outstanding Facility B Loans after such reduction
                  to the Facility B Commitment as so reduced. Any reduction of
                  the Commitment to zero shall be accompanied by payment of all
                  outstanding Obligations (and furnishing of cash collateral
                  satisfactory to the Lender for all L/C Obligations).

                  2.4.     FORM OF FACILITY B NOTE. The Credit Agreement is
         hereby further amended by deleting the Form of Facility B Note
         attached thereto as Exhibit A-2, and substituting in lieu thereof a
         new Exhibit A-2 in the form of Exhibit A-2 attached hereto.

                  2.5.     NOTES. The Credit Agreement is hereby further
         amended by deleting subsection 2.4(b) thereof in its entirety, and
         substituting in lieu thereof the following new subsection 2.4(b) to
         read as follows:

                           (b)      The Facility B Loans and the obligation of
                  the Borrower to repay the Facility B Loans shall be evidenced
                  by a Facility B Note executed by the Borrower payable to the
                  order of the Lender representing the Borrower's obligation to
                  pay the Facility B Commitment or, if less, the aggregate
                  unpaid principal amount of all Facility B Loans made and to
                  be made to the Borrower hereunder, plus interest and all
                  other fees, charges and other amounts due thereon. The
                  Facility B Note shall be dated the Sixth Amendment Effective
                  Date and shall bear interest on the unpaid principal amount
                  thereof at the applicable interest rate per annum specified
                  in Section 4.1.

         3.       ARRANGEMENT FEES. In consideration of Lender entering into
this Amendment, Borrower hereby agrees to pay the following arrangement fees to
Lender in lieu of the fixed arrangement fee set forth in Section 4.1 of the
First Amendment and the contingent arrangement fee set forth in Section 5.1 of
the Second Amendment:

                  3.1.     FIXED ARRANGEMENT FEE. Borrower agrees to pay a
         fixed arrangement fee equal to $750,000 payable on the later to occur
         of (a) the Facility B Termination Date and (b) the Termination Date.
         Borrower and each Guarantor hereby acknowledges and agrees that such
         fee has been fully earned by Lender, is non-refundable, and is
         irrevocably payable on the due date thereof without offset, deduction
         or counterclaim.

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                  3.2.     CONTINGENT ARRANGEMENT FEE. Borrower also agrees to
         pay a contingent arrangement fee: (a) equal to $200,000 upon the
         failure of Borrower to deliver to the Lender by April 15, 2000 a bona
         fide, letter of intent executed by all parties thereto for the sale of
         assets or stock of the Borrower that generates sufficient proceeds to
         pay the Obligations in full; and (b) equal to $200,000 upon the
         failure of Borrower to deliver to the Lender by June 15, 2000 a bona
         fide, definitive contract executed by all parties thereto for the sale
         of assets or stock of the Borrower that generates sufficient proceeds
         to pay the Obligations in full.

         4.       CONDITIONS PRECEDENT. The amendments contained herein shall
not become effective unless and until the Lender shall have received each of
the following instruments, documents and agreements:

                  (a)      this Amendment, duly executed and delivered by the
         Borrower and each Guarantor;

                  (b)      the Facility B Note, duly executed and delivered by
         the Borrower;

                  (c)      a certificate from the chief executive officer or
         chief financial officer of the Borrower, in form and substance
         satisfactory to the Lender, to the effect that all representations and
         warranties of the Borrower contained in the Credit Agreement, this
         Amendment and the other Loan Documents are true, correct and complete;
         that giving effect to this Amendment the Borrower is not in violation
         of any of the covenants contained in the Credit Agreement and the
         other Loan Documents; and that, after giving effect to this Amendment,
         no Default or Event of Default has occurred and is continuing;

                  (d)      a certificate of the secretary or assistant
         secretary of each Credit Party certifying that (i) the certificate or
         articles of incorporation and by-laws of such Credit Party, or the
         comparable organizational documents of such Credit Party, have not
         been amended, modified or supplemented since the Closing Date and (ii)
         attached thereto is a true and complete copy of resolutions duly
         adopted by the Board of Directors of such Credit Party authorizing the
         execution, delivery and performance of this Amendment and the other
         instruments, documents and agreements executed and delivered pursuant
         hereto or in connection herewith to which it is a party (collectively,
         the "Amendment Documents"), and ratifying the execution and delivery
         of this Amendment; and as to the incumbency and genuineness of the
         signature of each officer of such Credit Party executing the Amendment
         Documents to which it is a party;

                  (e)      a legal opinion of counsel to the Borrower in form
         and substance acceptable to the Lender; and

                  (f)      such other instruments, documents and agreements as
         the Lender may reasonably request.

         5.       REPRESENTATIONS AND WARRANTIES; NO DEFAULT. Each Credit Party
hereby jointly and severally represent and warrant to the Lender that (a) all
of Credit Parties' representations and warranties contained in the Credit
Agreement, the other Loan Documents and this Amendment are

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true and correct on and as of the date of this Amendment (or, if any such
representation or warranty is expressly stated to have been made as of a
specific date, as of such specific date) except, in the case of the
representation set forth in Section 6.1(q) of the Credit Agreement, as
reflected in the Borrower's interim financial statements for the period ending
November 30, 1999; (b) no Default or Event of Default has occurred and is
continuing as of such date under any Loan Document; (c) each Credit Party has
the power and authority to enter into this Amendment and the other Amendment
Documents to which it is a party and to perform all of its obligations
hereunder and thereunder; (d) the execution, delivery and performance of this
Amendment and the Amendment Documents have been duly authorized by all
necessary corporate or partnership action on the part of each Credit Party; (e)
this Amendment and the Amendment Documents are the legal, valid and binding
obligations of the Credit Parties party thereto, enforceable in accordance with
their respective terms, except as such enforcement may be limited by
bankruptcy, insolvency, reorganization, moratorium or similar state or federal
debtor relief laws from time to time in effect which affect the enforcement of
creditors' rights in general and the availability of equitable remedies; and
(f) the execution and delivery of this Amendment and the Amendment Documents
and performance thereof by the Credit Parties do not and will not violate the
Certificate or Articles of Incorporation, By-laws or other organizational
documents of any Credit Party and do not and will not violate or conflict with
any law, order, writ, injunction, or decree of any court, administrative agency
or other governmental authority applicable to any Credit Party or its
properties.

         6.       REAFFIRMATION OF LOAN DOCUMENTS.

                  (a)      Each Credit Party other than American European
         acknowledges and agrees that the portion of the Obligations of
         Borrower arising under Facility B or under this Amendment, including,
         but not limited to, the Facility B Loans:

                           (i)      are included in the "Guaranteed
                  Obligations," as such term is defined in the Guaranty, and
                  are guaranteed by the Guaranty;

                           (ii)     are included in the "Secured Obligations,"
                  as such term is defined in the Security Agreement, and are
                  secured by the Security Agreement;

                           (iii)    are included in the "Secured Obligations,"
                  as such term is defined in the Pledge Agreement, and are
                  secured by the Pledge Agreement;

                  (b)      Lender, American European and the other Credit
         Parties agree that the obligations of American European under the
         Guaranty, Security Agreement and Pledge Agreement are limited to that
         portion of the Obligations arising under Facility A or otherwise
         arising out of the Credit Agreement and the Loan Documents but not
         arising out of the Facility B.

                  (c)      Each Credit Party hereby reaffirms its obligations
         under the Loan Documents, and acknowledges and agrees that each of the
         Loan Documents to which such Credit Party is a party, and the
         obligations of such Credit Party thereunder, remain in full force and
         effect, without release, diminution or impairment, notwithstanding the

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         execution and delivery of this Amendment or of any prior amendment to
         the Credit Agreement or any other Loan Document.

         7.       REFERENCES. All references in the Credit Agreement and the
Loan Documents to the Credit Agreement shall hereafter be deemed to be
references to the Credit Agreement as amended hereby and as the same may
hereafter be amended from time to time.

         8.       LIMITATION OF AGREEMENT. Except as especially set forth
herein, this Amendment shall not be deemed to waive, amend or modify any term
or condition of the Credit Agreement, each of which is hereby ratified and
reaffirmed and which shall remain in full force and effect, nor to serve as a
consent to any matter prohibited by the terms and conditions thereof.

         9.       COUNTERPARTS. This Amendment may be executed in any number of
counterparts, and any party hereto may execute any counterpart, each of which,
when executed and delivered, will be deemed to be an original and all of which,
taken together will be deemed to be but one and the same agreement.

         10.      FURTHER ASSURANCES. Borrower agrees to take such further
action as the Lender shall reasonably request in connection herewith to
evidence the amendments herein contained to the Credit Agreement.

         11.      SUCCESSORS AND ASSIGNS. This Agreement shall be binding upon
and inure to the benefit of the successors and permitted assigns of the parties
hereto.

         12.      GOVERNING LAW. This Agreement shall be governed by, and
construed in accordance with, the laws of the State of Georgia, without regard
to principles of conflicts of law.

         13.      NO CLAIM. Each Credit Party hereby represents, warrants,
acknowledges and agrees to and with the Lender that as of the date hereof (a)
such Credit Party neither holds nor claims any right of action, claim, cause of
action or damages, either at law or in equity, against the Lender, its
officers, directors, agents, employees or Affiliates, or any of them, which
arises from, may arise from, allegedly arise from, are based upon or are
related in any manner whatsoever to the Credit Agreement and the Loan Documents
or which are based upon acts or omissions of the Lender, any such officer,
director, agent, employee or Affiliate of Lender, or any of them, in connection
therewith and (b) the Obligations are absolutely owed to the Lender, without
offset, deduction or counterclaim.

                  [Remainder of page intentionally left blank]

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         IN WITNESS WHEREOF, the parties hereto have executed this Amendment
under seal as of the date first written above.

                                CREDIT PARTIES:

                                BORROWER:

                                EDUTREK INTERNATIONAL, INC.

                                By:  S. Bostic
                                    ----------------------------------------
                                    R. Steven Bostic
                                    Chairman of the Board and
                                    Chief Executive Officer

                                Attest:  David J. Horn
                                        ------------------------------------
                                        David J. Horn
                                        Secretary and Chief Financial Officer

                                [CORPORATE SEAL]

                                GUARANTORS:

[CORPORATE SEAL]                EDUTREK SYSTEMS, INC.

                                By:  S. Bostic
                                    ----------------------------------------
                                    R. Steven Bostic
                                    Chief Executive Officer

[CORPORATE SEAL]                AMERICAN INTERCONTINENTAL
                                UNIVERSITY, INC.

                                By:  S. Bostic
                                    ----------------------------------------
                                    R. Steven Bostic
                                     Chief Executive Officer

[CORPORATE SEAL]                AMERICAN COLLEGE IN LONDON, LTD, U.S.

                                By:  S. Bostic
                                    ----------------------------------------
                                    R. Steven Bostic
                                    Chief Executive Officer

[CORPORATE SEAL]                AMERICAN EUROPEAN MIDDLE EAST
                                CORPORATION, LLC

                                By:    American College in London, Ltd., U.S.

                                        By:   S. Bostic
                                             -------------------------------
                                             R. Steven Bostic
                                             Chief Executive Officer

                                LENDER:

                                FIRST UNION NATIONAL BANK

                                By:  Frank Darrow
                                    ----------------------------------------
                                    Frank Darrow
                                    Vice President

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                                                                 EXHIBIT A-2 TO

                                            SIXTH AMENDMENT TO CREDIT AGREEMENT

                                    FORM OF
                                   FACILITY B
                             REVOLVING CREDIT NOTE

$4,350,000                                                  Atlanta, Georgia
                                                       9th day of February, 2000

         FOR VALUE RECEIVED, the undersigned (the "Borrower") HEREBY PROMISES
TO PAY to the order of FIRST UNION NATIONAL BANK (the "Lender"), the principal
amount of Four Million Three Hundred Fifty Thousand Dollars ($4,350,000), or,
if less, the aggregate unpaid principal amount of all "Facility B Loans"
disbursed to the Borrower by the Lender under, and as such term is defined in,
the Credit Agreement referred to below.

         The Borrower promise to pay interest on the unpaid principal amount
hereof until such principal amount is paid in full, at such interest rates, and
payable at such times, as are specified in the Credit Agreement. Nothing in
this Note shall be deemed to establish or require the payment of a rate of
interest in excess of the maximum rate permitted by any Applicable Law. In the
event that any rate of interest required to be paid hereunder exceeds the
maximum rate permitted by Applicable Law, the provisions of the Credit
Agreement relating to the payment of interest under such circumstances shall
control.

         Both principal and interest are payable in lawful money of the United
States of America to First Union National Bank in federal or other immediately
available funds.

         This Note is the Facility B Note referred to in, and is entitled to
the benefits of, the Credit Agreement dated as of March 25, 1999 (together with
all amendments and other modifications from time to time made thereto, the
"Credit Agreement"), among the Borrower and First Union National Bank, as
amended through and including the date hereof. Capitalized terms not defined
herein are to have the meanings provided to them in the Credit Agreement. The
Credit Agreement contains, among other things, provisions for the time, place
and manner of payment of this Note, the determination of the interest rate
borne by and fees payable in respect of this Note, acceleration of the payment
of this Note upon the happening of certain stated events and the mandatory
repayment of this Note under certain circumstances.

         The Borrower hereby agrees to pay on demand all reasonable costs and
expenses actually incurred by the Lender in collecting the Borrower's
obligations hereunder or in enforcing or attempting to enforce any of the
Lender's rights hereunder, including, but not limited to, reasonable attorneys'
fees and expenses actually incurred by the Lender if collected by or through an
attorney, whether or not suit is filed.

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                                                                 EXHIBIT A-2 TO

                                            SIXTH AMENDMENT TO CREDIT AGREEMENT

         Presentment for payment, notice of dishonor, protest and notice of
protest are hereby waived.

         THIS NOTE IS MADE AND DELIVERED IN THE STATE OF GEORGIA AND SHALL BE
GOVERNED BY, CONSTRUED AND ENFORCED IN ACCORDANCE WITH THE LAWS OF THE STATE OF
GEORGIA WITHOUT REFERENCE TO THE CONFLICTS OR CHOICE OF LAW PRINCIPLES THEREOF.

         IN WITNESS WHEREOF, the Borrower has caused this Note to be executed
under seal by a duly authorized officer as of the day and year first above
written.

[CORPORATE SEAL]                                 EDUTREK INTERNATIONAL, INC.

ATTEST:

By:                                              By:
    --------------------------------------           ---------------------------
    David J. Horn                                    R. Steven Bostic
    Secretary and Chief Financial Officer            Chairman of the Board and
                                                     Chief Executive Officer

                                       2<PAGE>   1

                                                                  EXHIBIT 10.67

                  FIRST AMENDMENT TO MASTER AGREEMENT TO LEASE

        THIS FIRST AMENDMENT TO MASTER AGREEMENT TO LEASE ("Amendment") is made
and entered into as of the 31st day of December, 1999, by and between PRISON
REALTY TRUST, INC. (formerly Prison Realty Corporation), a Maryland corporation
("Landlord") and CORRECTIONS CORPORATION OF AMERICA (formerly Correctional
Management Services Corporation), a Tennessee corporation ("Tenant").

                              W I T N E S S E T H:

        WHEREAS, Landlord and Tenant have previously entered into the Master
Agreement to Lease, dated January 1, 1999 (the "Master Agreement"), which sets
forth certain terms and conditions pursuant to which Landlord leases certain
properties to the Tenant; and

        WHEREAS, Landlord and Tenant now desire to amend certain terms and
provisions of the Master Agreement, as more particularly set forth herein.

        NOW, THEREFORE, in consideration of the foregoing and their respective
agreements and undertakings herein, and other good and valuable consideration,
the receipt and sufficiency of which is hereby acknowledged, Landlord and Tenant
hereby agree as follows:

        1. Section 2.02 of the Master Agreement shall be deleted in its entirety
and the following shall be inserted in lieu thereof:

               2.02 Additional Rent. On each Rent Escalation Date (as defined in
        each Lease), the Tenant shall pay Landlord an amount (the "Additional
        Rent") each year equal to the lesser of (i) four percent (4%) of the
        Total Rent (for the purposes hereof Total Rent is equal to the product
        of (a) the aggregate rental payments due and payable by Tenant to
        Landlord for the month immediately preceding the Rent Escalation Date
        and (b) twelve (12)) or (ii) ten percent (10%) of the excess of the
        Tenant's aggregate gross management revenues for the prior year over the
        Tenant's Base Revenue (for purposes hereof, the Tenant's Base Revenue
        shall be $325,000,000). The Additional Rent shall be payable monthly,
        along with Base Rent, and otherwise in the manner as set forth in
        Section 2.01 above. Tenant shall provide to Landlord, not later than
        thirty (30) days following each Rent Escalation Date, Tenant's
        statement, certified by Tenant's chief financial officer, setting forth
        Tenants' aggregate gross management revenues for each prior year.

        2. Except as specifically modified or amended herein, all terms and
provisions of the Master Agreement shall continue and remain in full force and
effect.

                         [signatures on following page]

<PAGE>   2

        IN WITNESS WHEREOF, the parties hereto have executed this Amendment as
of the date first set forth above:

                                    LANDLORD:

                                    PRISON REALTY TRUST, INC.

                                    By: /s/ Doctor R. Crants
                                       -----------------------------------------

                                    Its: Chief Executive Officer
                                         ---------------------------------------

                                     TENANT:

                                     CORRECTIONS CORPORATION OF AMERICA

                                     By: /s/ Darrell K. Massengale
                                        ----------------------------------------

                                     Its: Chief Financial Officer and Secretary
                                         ---------------------------------------

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