Chaco Canyon was a major center of Puebloan culture between AD 850 and 1250. The Chacoan sites are part of the homeland of Pueblo Indian peoples of New Mexico, the Hopi Indians of Arizona, and the Navajo Indians of the Southwest. Chaco Culture National Historical Park is a United States National Historical Park and a UNESCO World Heritage Site hosting the densest and most exceptional concentration of pueblos in the American Southwest. The park is located in northwestern New Mexico, between Albuquerque and Farmington, in a relatively inaccessible canyon cut by the Chaco Wash. Containing the most sweeping collection of ancient ruins north of Mexico, the park preserves one of America's most fascinating cultural and historic areas.[1]..Between AD 900 and 1150, Chaco Canyon was a major center of culture for the Ancient Pueblo Peoples.?[?] Chacoans quarried sandstone blocks and hauled timber from great distances, assembling fifteen major complexes which remained the largest buildings in North America until the 19th century.[1][2] 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,[3] requiring generations of astronomical observations and centuries of skillfully coordinated construction.[4] 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 in 1130.[5]..Located in the arid and inhospitable Four Corners region, the Chacoan cultural sites are fragile; fears of erosion caused by tourists have led to the closure of Fajada Butte to the public. The sites are considered sacred ancestral homelands of the Hopi and Pueblo people, who continue to maintain oral traditions recounting their historical migration from Chaco and their spiritual relationship to the land.[6][7] Though park preservation efforts can conflict with native religious