2005 Mesa Verde National Park, CO

Mesa Verde (Spanish for green table), occupies just over 52,000 acres of the Colorado Plateau. The correct geological term for the area is cuesta. Cuestas are similar to mesas, but instead of being relatively flat, they gently dip in one direction. Mesa Verde is inclined slightly to the south at about a seven degree angle and has been highly dissected by wind and water erosion into a series of canyons and “mesas.” Elevations range from about 6,000 feet in the canyon bottoms near the southern park boundary to 8,572 feet at Park Point, about ten miles north.

The cliff dwellings of Mesa Verde are some of the most notable and best preserved in the North American Continent. Sometime during the late 1190s, after primarily living on the mesa top for 600 years, many Ancestral Puebloans began living in pueblos they built beneath the overhanging cliffs. The structures ranged in size from one-room storage units to villages of more than 150 rooms. While still farming the mesa tops, they continued to reside in the alcoves, repairing, remodeling, and constructing new rooms for nearly a century. By the late 1270s, the population began migrating south into present-day New Mexico and Arizona. By 1300, the Ancestral Puebloan occupation of Mesa Verde ended.

Sandstone, mortar and wooden beams were the three primary construction materials for the cliff dwellings. The Ancestral Puebloans shaped each sandstone block using harder stones collected from nearby river beds. The mortar between the blocks is a mixture of local soil, water and ash. Fitted in the mortar are tiny pieces of stone called "chinking." Chinking stones filled the gaps within the mortar and added structural stability to the walls.