Mesa Verde National Park in southwestern Colorado is one of the major archeological preserves in the United States. The park consists of more than 4,000 ruin sites, which include 600 cliff dwellings. Mesa Verde, Spanish for "green table", is so called because of its comparatively level top and is heavily forested.

A score of large canyons seam the mesa, and in the shelter of the hundreds of alcoves eroded in the cliffs are some of the world’s largest and best preserved cliff dwellings. Archeologists have stabilized only a few of the ruins.

The earliest known inhabitants of Mesa Verde were the Modified Basket Makers, descendants of the Anasazi people. They built subterranean pithouses about A.D. 500-750. From A.D. 750 to 1100, the Native Americans perfected their living quarters, building kivas (ceremonial rooms) and masonry houses around open courts (pueblos). From 1100 to 1300, arts and crafts reached their peak, pottery and clothes were often elaborately decorated. Around 1200 they moved into the alcoves and built cliff dwellings. Sometime about 1276 a drought struck and lasted 24 years. The resulting crop failures and other environmental problems may have driven the people from Mesa Verde in search of a more reliable water supply.

Similar cliff dwellings can be found at Montezuma Castle, Canyon de Chelly,  Bandelier and Navajo. 

Another major architectural site can be found in the remote Chaco Canyon National Monument in New Mexico. In Chaco Canyon prehistoric Anasazi people established a ritual and cultural center. The Monument occupies 34 square miles and contains 13 major Anasazi ruins and hundreds of smaller ones. Pueblo Bonito ruin dates back to A.D. 900s. Pueblo Bonito was once four stories high, contained 800 rooms, 32 kivas. 

The best preserved pueblos in the Southwest area: Taos, Acoma, in the valley of Rio Grande, San Felipe, Santo Domingo and Zia.

Mexican pyramids did not necessarily resemble the familiar form of the Egyptian variety. Created essentially as religious monuments, they frequently had steps built into the sides. Exterior carvings not only served as decoration but also depicted historical and mythological events. The ceremonial centers from which these pyramids rose were dedicated to fanciful gods and paid tribute to the priest rulers who presided over rigidly hierarchical societies.

The Yucatan Peninsula’s best known and most visited ruins are the remains of a great Maya city and one of the archeological wonders of the world. Of the several hundred buildings occupying the site, about 30 have been fully restored. The others have been partially restored, remain as they were found or are merely rough mounds hidden beneath tangled underbrush.

It is believed that Chichen Itza was founded sometime around A.D. 435. After being abandoned for an undetermined length of time, it was rediscovered and firmly established as an important ceremonial center. Many archeologists believe that the gradual decline of Maya theocratic rule allowed the more warlike Toltecs from central Mexico to occupy the city around the beginning of the 11^th century, and that under Toltec rule Chichen Itza became the religious, political and cultural center of the Yucatan.

High in the Andes the Inca erected what is probably the most spectacular work of engineering in all of ancient America. Straddling a narrow ridge between two mountain peaks, the fabled city of Machu Picchu rises 2,000 feet above the valley of the Urubamba River. The only access to the city, whose history and function are unknown, was a narrow road that winds along the tops of the Andes themselves.

Machu Picchu’s architecture testifies to the ingenuity of its builders. Stoneworkers quarried hard granite blocks from the mountaintop for the city’s more than 100 acres of buildings, walls and plazas, cut level foundations into the rock and raised huge masses of close-fitting stones. Stairways were carved into the mountain face to connect places, temples, military barracks and homes; fountains fed by aqueducts supplied the inhabitants with water. To make the city as self-sufficient as possible, the steep slopes below it were banked with rows of narrow agricultural terraces, whose retaining walls also formed multiple defense lines against attack.