Mesa Verde is a US national park located in the Montezuma County in Colorado, which was designated UNESCO World Heritage Site. This park contains very well preserved archeological sites related to the Ancestral Puebloan.
The Ancestral Puebloan was a native American culture which populated the current region of the Four Corners, which includes the part of the nowadays territories of four US states: Utah, Arizona, New Mexico, and Colorado. These people lived in cliff-sited dwellings, established like that for defense purpouses, which included small family pit houses that formed larger structure to house complete clans. The photo attached shows the display of those settlements.