The Anasazi, an ancient Pueblo people, built cliff towns in the southwest United States that remain well preserved due to arid conditions. The civilization collapsed at the end of the 13th century. The word Anasazi comes from the Navajo language and means "enemy ancestors."
Rancher Richard Wetherill explored some of the ancient Anasazi sites, including Mesa Verde, and gave the culture its current name, as he worked with local Navajos. The Anasazi culture is related to the Mogollon and Hohokam cultures, which also started settling in permanent towns during the first millennium. Mesoamerican civilizations may have influenced southwestern cultures to adopt agriculture and settle in permanent towns.
The Anasazi left a permanent mark on the landscape with grand cliff towns, and archaeologists also remark upon its beautiful basketry. By building towns in canyon walls and ledges, the Anasazi separated and defended themselves from nomadic tribes such as the Navajo. The Anasazi planted their crops in well-irrigated river valleys below their towns. Many Anasazi traditions passed down to the modern Pueblo people.
Archaeologists do not fully understand why the Anasazi eventually abandoned their cliff towns during the 13th century. Originally it was thought that prolonged drought forced matters; however recent research contradicts a collapse based on climate alone. Some archaeologist think that a slightly drier climate, along with overfarming, led to an increasingly divided civilization and internal war. Others theorize that there may have been religious strife, as Anasazi descendant cultures did not build the same religious structures.