Of the ancient American civilizations, the greatest in territorial extent, and the one with the most tightly knit society, was developed by the Incas of South America. It embraced the ranges and plateus of the Andes, the mountainous heart of the continent, and at its height included northern portions of Argentina and Chile. To convert such a rocky terrain into productive cropland and to unify a territory so fragmented by geography was a challenging task, yet it was successfully accomplished. Inca civilization, though destined for destruction, left a permanent mark upon the regions it occupied. As with the Mayas and Aztecs of Mexico and Central America, the Incas were beneficiaries of a cultural heritage from a number of other Indian people. About 1000 B.C., when the Olmecs brought their civilization to the Gulf Coast of Mexico, a culture known as the Chavin was founded on the slopes of the northern Peruvian highlands, where it continued for 500 years or more. Keywords: American civilization, groups, Maya, inhabitants, nomadic stages, peninsula, absorbed, Teotihuacan civilization, Mesoamerica, contributions, indebted, Christian era, ceremonial display, architectural skill, pyramids, calendrical inscription, analogous, sacred rites, common features, developed, principle, conquerors, alien culture