65 ILCS 5/11-106-1

In all municipalities with 500,000 or more inhabitants, the corporate authorities may enter into any contract with any person for the purpose of arranging for the holding of any general public exhibitions, concerts, dances, entertainments, or celebrations in the municipality or on any pier owned or controlled by the municipality extending out into any lake or harbor adjacent to the municipality, and to provide for the payment of any expense necessarily incurred in contracting for the holding of any of the specified events out of the miscellaneous receipts of the municipality which have not been otherwise appropriated.