The cities, villages, townships and counties aforesaid, acting under the provisions of this act, shall have power and are hereby authorized, through their proper agents, servants and employes to enter into the necessary contracts with each other and with other persons for the acquiring and maintaining of a building or the acquiring of a site or sites and the erection, construction and maintenance, either jointly or severally, in any manner which may be necessary and which they shall deem expedient for the purpose of establishing and maintaining joint ownership, operation and maintenance of a building or buildings to be used for public purposes to the extent and in the manner now provided by law.