<PAGE>
                                                                  Exhibit 10(gg)

                                PROMISSORY NOTE
                                ---------------

$25,000,000                                            Dated:  September 1, 2000


         FOR VALUE RECEIVED, the undersigned, GGP LIMITED PARTNERSHIP, a
Delaware limited partnership, and GGPLP L.L.C., a Delaware limited liability
company (collectively, the "Borrower"), jointly and severally, HEREBY PROMISE TO
PAY to the order of BAYERISCHE Hypo- und Vereinsbank, NEW YORK BRANCH (the
"Lender"), on the Maturity Date, the aggregate principal amount (or so much
thereof as is then outstanding) of TWENTY-FIVE MILLION AND NO/100 DOLLARS
($25,000,000), which is the total amount of the Loans made by the Lender to the
Borrower pursuant to that certain Credit Agreement dated as of July 31, 2000, by
and among the Borrower, the Lender, and the other financial institutions from
time to time parties thereto as Lenders and Bank of America, N.A., as
Administrative Agent (as the same may be amended, restated, supplemented, or
otherwise modified from time to time, the "Credit Agreement"). Capitalized terms
used herein, and not otherwise defined herein, shall have the meanings ascribed
to such terms in the Credit Agreement.

         The Borrower further promises to pay interest on the unpaid principal
amount of each Loan from the date advanced until such principal amount is paid
in full, at such interest rates (which shall not exceed the maximum rate
permitted by Illinois law), and at such times, as are specified in the Credit
Agreement.

         All payments of principal and interest in respect of this Promissory
Note shall be made to the Administrative Agent in lawful money of the United
States of America in same day funds for the account of the Lender in accordance
with the terms of the Credit Agreement. Each Loan made by the Lender to the
Borrower pursuant to the Credit Agreement, and all payments made on account of
principal thereof, shall be recorded by the Lender on its books and records and,
if the Lender so elects in connection with any transfer or enforcement hereof,
appropriate notations to evidence the foregoing information with respect to each
such Loan then outstanding may be endorsed by the Lender on a schedule to be
attached hereto by the Lender and thereby made a part hereof, or on a
continuation of such schedule to be attached to and made a part hereof; provided
that the failure of the Lender to make any such recordation or endorsement shall
not affect the obligations of the Borrower hereunder or under the Credit
Agreement.

         This Promissory Note is one of the Notes referred to in, is executed
and delivered pursuant to, and is entitled to the benefits of, the Credit
Agreement, to which Credit Agreement reference is hereby made for a statement of
the terms and conditions under which this Promissory Note may be prepaid or the
Obligations accelerated or extended. The terms and conditions of the Credit
Agreement are hereby incorporated in their entirety herein by reference as
though fully set forth herein. Upon the occurrence of certain Events of Default
as more particularly described in the Credit Agreement, the unpaid principal
amount evidenced by this Promissory Note shall become, and upon the occurrence
and during the continuance of certain other Events of Default, such unpaid
principal amount may be declared to be, due and payable in the manner, upon the
conditions and with the effect provided in the Credit Agreement.
<PAGE>

         Demand, presentment, diligence, protest and notice of nonpayment are
hereby waived by the Borrower.

         THIS PROMISSORY NOTE SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE
WITH, THE LAWS OF THE STATE OF ILLINOIS.

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

                             GGPLP L.L.C., a Delaware limited liability company

                             By:    GGP LIMITED PARTNERSHIP, a
                                    Delaware limited partnership, its sole
                                    managing member

                             By:    GENERAL GROWTH PROPERTIES, INC.,
                                    a Delaware corporation, its sole general
                                    partner

                             By: ___________________________________________
                             Name:  Bernard Freibaum
                             Title: Executive Vice President


                               GGP LIMITED PARTNERSHIP, a Delaware limited
                               partnership

                               By:    GENERAL GROWTH PROPERTIES, INC.,
                                      a Delaware corporation, its sole general
                                      partner

                               By: ___________________________________________
                               Name:  Bernard Freibaum
                               Title: Executive Vice President

                                      -2-