The document provides background information on three major civilizations in Central and South America from 2000 BC to the 16th century: the Mayas, Aztecs, and Incas. It discusses their empires, important cities, architecture, economies based on agriculture, and religious practices including human sacrifices. Key achievements included the Mayas' accurate calendar, the Aztecs' large empire and city of Tenochtitlan built on a lake, and the Incas' extensive road network and mountainside agriculture. All three civilizations introduced new crops to Europe and had social hierarchies and tax systems led by religious and wealthy elites.