The document provides information about three early American civilizations:
The Maya civilization flourished from 250-900 AD in Central America, developing one of the few fully written languages of the Americas as well as advanced mathematical, astronomical and architectural achievements. However, they mysteriously declined around 900 AD.
The Aztec civilization dominated central Mexico from 1250-1521 AD, practicing intensive agriculture and human sacrifice on a large scale while expanding their influence.
The Inca civilization spanned Peru and Chile from 1220-1532 AD, emphasizing a centrally managed economy focused on agriculture and redistribution of wealth over military conquest, with a polytheistic religion centered on sun worship.