The document summarizes several ancient civilizations of Central and South America including the Olmec, Maya, Inca, and Aztec. The Olmec were among the earliest peoples in Mexico, building pyramids and temples and trading jade and obsidian. The Maya inhabited parts of Central America and had advanced calendars, mathematics, and hieroglyphic writing. The Inca Empire spanned western South America with impressive architecture and road systems. The Aztec rose to power in central Mexico, building the large city of Tenochtitlan and practicing human sacrifice of war captives to their gods. The Spanish conquistadors led by Cortes and Pizarro conquered these civilizations within a century, introducing Christianity, slavery