Photo: Chaco Canyon National Historical Park, Aerial View
Located in northwestern New Mexico, Chaco Culture National Historical Park became part of the US national park system (as a national monument) in 1907 and was designated a World Heritage Site in 1987.
Elevation: 6,200 feet
The Chaco Culture National Historic Park is regarded as the cultural center of the ancestral Puebloan people, who inhabited the region from about 900 to 1150 A.D. The 30,000-acre park has the most dense and concentrated collection of archaeological sites in the US Southwest.