AP United States History

By 1491 the Americas held tens of millions of people, divided into hundreds of societies with distinct languages, economies and political systems. Historians do not agree on a single population figure for North America north of Mexico, and estimates run from a few million to well over ten million, but they agree that the continent was densely settled in many regions and that the peoples of the Americas had developed complex ways of using their environments. The first migrants had arrived from Asia many thousands of years earlier, probably across the land bridge called Beringia during the last Ice Age and perhaps also along the Pacific coast, and over the following millennia their descendants spread across both continents. ## Agriculture as the basis of complex societies Societies that grew maize (corn) could support larger populations, permanent towns and specialized work. Maize was first domesticated in central Mexico thousands of years before European contact, and its cultivation spread north and south, usually alongside beans and squash. Where these crops could be grown, people lived in villages and cities, built monumental architecture and developed religious and political hierarchies. Where agriculture was impossible or poorly suited to the climate, people usually lived in smaller groups that hunted, fished and gathered, and moved with the seasons. The Aztec (Mexica) empire in the Valley of Mexico, with its capital Tenochtitlan on an island in a lake, and the Inca…