The mayor and city council of any city of the first class are hereby authorized to acquire by purchase or otherwise and hold in the name of the city, lands, lots, or grounds within or without the limits of the city to be used and improved for parks, parkways, or boulevards. To pay for and improve such lands, lots, or grounds, the mayor and city council are authorized to issue bonds for such purposes, except that no such bonds shall be issued until the question of issuing such bonds shall have been submitted to the electors of the city, at a general election therein, or at a special election appointed and called by the mayor and city council for such purposes, and a majority of electors voting at such election shall have voted in favor of issuing the bonds. Notice of such election shall be given by publication once each week for three successive weeks prior thereto in a legal newspaper in or of general circulation in such city. Such bonds shall be payable in not to exceed twenty years from the date of issuance thereof, and shall bear interest payable annually or semiannually, with interest coupons attached to the bonds. The mayor and city council may at their discretion construct in any park a swimming pool, stadium, or other facilities for public use and recreation and pay for such facilities out of the proceeds of such bonds.