Aztec Ruins National Monument, archaeological site in northwestern New Mexico, U.S. It is situated on the Animas River, in the city of Aztec, about 10 miles (16 km) south of the Colorado state line. The national monument was established in 1923 and designated a World Heritage site in 1987 (along with Chaco Culture National Historical Park to the south). It has an area of about 320 acres (130 hectares).
Archaeological work began in 1916. Under the direction of Earl H. Morris of New York City’s American Museum of Natural History, the true story of Aztec Ruins was uncovered. Mistakenly considered to be Aztec in origin by early white settlers, the site actually contains the ruins of a 12th-century Ancestral Pueblo settlement built by people associated with Chaco Canyon to the south. The Ancestral Pueblo people, formerly known as Anasazi, were ancestors of the modern Pueblo Indians. They lived in pueblos, multilevel communal dwellings constructed of sandstone, mud, and stones. Pueblos consisted of numerous rooms and housed hundreds of people. Ladders made of timber were used to reach the upper levels. The site was used by people associated with the 13th-century inhabitants of what is now Mesa Verde National Park (to the northwest in southwestern Colorado) and was abandoned about 1300.
Aztec Ruins, about 2 miles (3.2 km) long and 1 mile (1.6 km) wide, contains multistory “great houses” as well as smaller pueblos. The West Ruin, open to visitors, once had more than 500 rooms centred on an open plaza (many of which still have their original wooden roofs) and held artifacts offering a glimpse into the lives of the Ancestral Pueblo people. The West Ruin also contains the 48-foot- (15-metre-) diameter Great Kiva, reconstructed by Morris in 1934. The kiva, a round subterranean structure used for community ceremonies, was central to the Ancestral Pueblo culture. Many artifacts are on display at the visitors’ centre. The large Navajo Reservation of Arizona, New Mexico, and Utah is just west of the site.