* 7th century Valley of Mexico
* Took over as power declined due to food shortages (Toltecs returned before Aztecs)
* Build island city Tenochtitlán in Lake Texcoco with
* complex political, military, and religious bureaucracy
* tax collectors, courts of justice, and mail service
* Aztecs require humans from city-states for labor, sacrifices for political intimidation
* Fine arts, massive stone statues, royal library with books documentary society