The Tyuonyi (chew-OHN-yee) structure was one to 2 stories high, contained 400 rooms and probably housed about 100 people. It is only one of several structures. At the center of this was a Kiva an important part of the ceremonial culture. It was the center of the community for religious activities, education and decision making. More info is at: http://www.americansouthwest.net/new_mexico/aztec_ruins/national_monument.html