Chaco Culture National Historical Park

Chaco Culture National Historical Park is a United States National Historical Park in the American Southwest hosting a large concentration of pre-Columbian indigenous ruins of pueblos. The park is in northwestern New Mexico, between Albuquerque and Farmington, in a remote canyon cut by the Chaco Wash. Containing the most sweeping collection of ancient ruins north of Mexico, the park preserves one of the most important cultural and historical areas in the United States.

Between 900 and 1150, Chaco Canyon was a major cultural center for the Ancestral Puebloans. Chacoans quarried sandstone blocks and hauled timber from great distances, assembling 15 major complexes that remained the largest buildings ever built in North America until the 19th century. Evidence of archaeoastronomy at Chaco has been proposed, with the "Sun Dagger" petroglyph at Fajada Butte a popular example. Many Chacoan buildings may have been aligned to capture the solar and lunar cycles, requiring generations of astronomical observations and centuries of skillfully coordinated construction. Climate change is thought to have led to the emigration of Chacoans and the eventual abandonment of the canyon, beginning with a 50-year drought that began in 1130.