 The 1966 act required those agencies to work in conjunction with the SHPO and an independent federal agency, the Advisory Council on Historic Preservation (ACHP) to confront adverse effects of federal activities on historic preservation.Another Interior agency, the National Park Service, had past experience overseeing the Historic American Buildings Survey (1933) and the Historic Sites Survey authorized in 1935.Because of this, and the fact that the Park Service was already managing numerous historic properties within national parks, the NPS was the logical choice to head up the newly created historic preservation program.