The site of Chaco Canyon is a large and important one, so various excavations have occurred over the years. The first one with major significance was done by Neil Judd and the National Geographic Society in 1921. For a period of seven years Judd and his crew worked at Chaco every summer. Their first task in 1921 was to study a thirteen foot trash dump that was composed of ceramic artifacts. When they finished this, they concentrated on the excavation of Pueblo Bonita (Frazier, p. 43).