The purpose of the Historic Preservation Overlay (HPO) zone is to preserve, protect, enhance, perpetuate, and promote the use of structures and areas of historical, cultural, architectural, engineering, archeological, or geographic significance located in the city; to strengthen the city's economic base by stimulating the tourist industry; to enhance the identity of the city by protecting the city's heritage and prohibiting the unnecessary destruction or defacement of its cultural assets; and to conserve existing urban developments as viable economic and social entities. Properties in this district have 1 or more of the following characteristics: