The whole Mesa Verde National Park, including Cliff Palace, is a UNESCO World Heritage Site. It is a plateau in south west Colorado which has a large number of Pueblo Indian cliff dwellings.
From the back of the card:
Mesa Verde, Spanish for "green table", offers a spectacular look into the lives of ancestral Puebloan people who made it their home for over 700 years from AD 600 to AD 1300. Today the park protects more than 4,700 known archeological sites, including some 600 cliff dwellings of which Cliff Palace is the largest and most picturesque.I have one other card showing the cliff dwelling known as Cliff Palace from a slightly different angle.