Section 2. Cities, by order of council or commissioners, shall have power to appropriate money, from the public funds or by issuance of bonds according to existing law governing the issuance of such bonds, for the erection, on said property taken, purchased, or acquired through condemnation proceedings, public auditoriums, public libraries, public memorial buildings, and monuments. Cities shall also have power to appropriate moneys for the operation and maintenance of such public auditoriums, public libraries, memorial buildings, and monuments.