The United States National Historic Landmark Program is designed to recognize and honor the nation's cultural and historical heritage. The program was formally inaugurated with a series of listings on October 9, 1960; as of February 16, 2017, there are 2,596 designated landmarks. A National Historic Landmark (NHL) is generally a building, district, object, site, or structure, that is officially recognized by the United States government for its national historical significance. A National Historic Landmark District (NHLD) is a historic district that is recognized as an NHL. Its geographic area may include contributing properties that are buildings, structures, sites or objects, and it may include non-contributing properties.