History of the Americas

Land Migration
Just when the migration started is subject to much debate. In theory it could have taken place as early as 40,000 BC, and recent archeological finds suggest multiple migrations, but the predominant theory is a single land migration starting around 20,000 BC. All theories agree that the Inuit arrived separately and much later, probably around the 6th century.

Although several large, centralized civilizations developed in the Western Hemisphere (e.g., the Inca in the Andes, the Aztecs and the Maya in Central America), the major North American mound building civilizations like the Cahokians had very few major population centers. The capital of the Cahokians, Cahokia - located near modern East St. Louis, Illinois may have reached a population of over 20,000. At its peak, between the 12th and 13th centuries Cahokia was the most populous city in North America. Monk's Mound, the major ceremonial center of Cahokia, remains the largest earthen construction of the prehistoric New World.

By the 15th century AD, corn had been transmitted from Mexico and was being farmed in the Mississippi River Valley, but further developments were cut short by the arrival of Europeans. Potatoes were utilized by the Inca and chocolate by the Aztec.

Europeans Discover the Americas
The continent was rediscovered by Europeans later. Initially the Vikings established a short-lived settlement in Newfoundland. Theories exist about earlier and later Old World discoveries of the east coast (or of the west coast by the Chinese), but none of these are considered proven. It was the later voyage of Christopher Columbus that led to extensive European colonization of the Americas. Europe sovereignty began to unravel on July 4, 1776 with the United States Declaration of Independence which was followed in the early 1800's by the independence of Haiti and several South American countries.