The "Cliff Palace" cliff dwelling, built by the clans of the Ancestral Puebloan Culture in the 12th century and abandoned within a cantury, in modern-day Mesa Verde National Park in Colorado. The complex of square dwellings and round sunken ceremonial kiva chambers is constructed of sandstone blocks, wooden beams, and mortar. As the largest cliff dwelling in North America, it is believed to have been a regional administrative and ceremonial center.