Mo. Rev. Stat. § 95.510
In the event that at any time the United States, or any qualified authority thereof, shall propose to establish and improve, within any city in this state now or hereafter having a population of four hundred thousand inhabitants or more, a national park or plaza, intended and designed to commemorate any great event or movement in our national history, to be accessible to the public under federal regulation, and to cover an area within such city of not less than one million square feet, and one thousand or more voters of such city shall petition the board of aldermen of such city, asking that the question be submitted to the voters to determine whether, in consideration of and in order to induce the location and establishment of such improved park or plaza in such city, the city shall incur indebtedness and evidence the same by the issuance of bonds for the purpose of providing funds to make the payment by way of assistance herein referred to, it shall be the duty of the board of aldermen as soon as conveniently may be, to submit the question to the voters.
§ 95.510, RSMo
RSMo 1939 § 15373, A.L. 1978 H.B. 971