Spruce Tree House, the third largest cliff dwelling (Cliff Palace and Long House are larger), was constructed between AD 1211 and 1278 by the ancestors of the Puebloan peoples of the Southwest. The dwelling contains about 130 rooms and 8 kivas (kee-vahs), or ceremonial chambers, built into a natural cave measuring 216 feet (66 meters) at greatest width and 89 feet (27 meters) at its greatest depth. It is thought to have been home for about 80 people. Mesa Verde, Spanish for green table, offers a spectacular look into the lives of the Ancestral Pueblo people who made it their home for over 700 years, from A.D. 600 to A.D. 1300. Today, the park protects over 4,000 known archeological sites, including 600 cliff dwellings. These sites are some of the most notable and best preserved in the United States. (Image taken with Canon EOS 20D at ISO 400, f5.6, 1/125 sec and 17mm)s (kee-vahs), or ceremonial chambers, built into a natural cave measuring 216 feet (66 meters) at greatest width and 89 feet (27 meters) at its greatest depth. It is thought to have been home for about 80 people. Mesa Verde, Spanish for green table, offers a spectacular look into the lives of the Ancestral Pueblo people who made it their home for over 700 years, from A.D. 600 to A.D. 1300. Today, the park protects over 4,000 known archeological sites, including 600 cliff dwellings. These sites are some of the most notable and best preserved in the United States. (Image taken with Canon EOS 20D at ISO 400, f4.0, 1/60 sec and 25mm)