"Historic property" means real property together with any improvements, except property listed in a register primarily for objects buried below ground, which is listed in the local register, certified by the United States Secretary of the Interior as provided in 16 U.S.C. 470, or listed in the National Register of Historic Places. (Added by Amended Ord. 06-037, Dec. 13, 2006, Eff date Jan. 5, 2007).