Ancestral Puebloans build Cliff Palace at Mesa Verde

After the decline of Chaco, Mesa Verde became one of the main centres of the Ancestral Puebloans. At the start of the 13th century some 22,000 people lived in the region, most of them in villages on the plains west of the mesa such as Yellow Jacket Pueblo; the population grew sharply in 1225–1260, and by 1260 most people lived in large pueblos of more than a hundred inhabitants. From the end of the 12th century many communities moved into alcoves in the canyon walls: most of the roughly 600 cliff dwellings in today's national park were built between about 1180 and 1300. The reasons are debated. The move into such defensible positions is often explained by increasing competition amid a changing climate, while the National Park Service stresses water: most cliff dwellings were built near seep springs, among the few permanent sources of water at Mesa Verde, at a time when droughts were making the reservoirs on the mesa top unreliable.

Cliff Palace is the largest of them. A few tree-ring dates from its timbers go back to 1190–1191, but construction mostly spanned the years from 1209 to at least 1280, with the main building phase in 1260–1280; Larry Nordby's architectural study dates the finished village to about 1278–1280. Older park texts put the work at 1190–1260, with most of it done in the first twenty years. The builders shaped sandstone blocks with harder stones, bound them with a mortar of soil, water and ash, and covered the walls with earthen plasters, traces of which survive in yellow, white and red. The National Park Service counts about 150 rooms and 23 kivas — round, sunken ceremonial chambers whose roofs rested on six stone pilasters, with a hearth, a ventilation shaft and a small hole in the floor, the sipapu. Estimates of its population range from about 100 to 125; the tallest of its towers, about 8 m high, almost reaches the roof of the alcove. The unusually high proportion of kivas to living rooms suggests that Cliff Palace was a centre for a wider community of nearby pueblos. Across Fewkes Canyon stands the D-shaped Sun Temple, and from a platform at the south end of Cliff Palace the winter-solstice sun can be seen setting over it.

The finished village was not lived in for long. After 1250 the usual pattern of summer rains and winter snows had begun to fail, after 1270 the climate turned markedly colder, and violence peaked in 1275–1285; the last timber for building on the mesa was felled in 1281, and by about 1285–1300 the inhabitants had left for the south (see the Great Drought of 1276–1299). The ruin was rediscovered on 18 December 1888 by two cowboys, Richard Wetherill and his brother-in-law Charlie Mason, who were looking for stray cattle. Visitors damaged its walls and carried off artefacts, and concern for the site helped bring about the creation of Mesa Verde National Park in 1906; Cliff Palace was stabilised between 1908 and 1922, and the park became a UNESCO World Heritage Site in 1978.