<human>:  When did they build the cliff dwellings in Mesa Verde?
<bot>: The cliff dwellings in Mesa Verde were built between 600 and 1300 AD. The Ancestral Pueblo people, who lived there, were a group of hunter-gatherers who settled in the area around AD 500. The Ancestral Pueblo people built the cliff dwellings, which were used as homes, as well as religious sites.