United States (History), story of how the republic developed from colonial beginnings in the 16 th century, when the first European explorers arrived, until modern times. As the nation developed, it expanded westward from small settlements along the Atlantic Coast, eventually including all the territory between the Atlantic and Pacific oceans across the middle of the North American continent, as well as two noncontiguous states and a number of territories. At the same time, the population and the economy of the United States grew and changed dramatically. The population diversified as immigrants arrived from all countries of the world. From its beginnings as a remote English colony, the United States has developed the largest economy in the world. Throughout its history, the United States has faced struggles, both within the country-between various ethnic, religious, political, and economic groups-and with other nations.

The efforts to deal with and resolve these struggles have shaped the United States of America into the 21 st century. This is one of seven major articles that together provide a comprehensive discussion of the United States of America. For more information on the United States, please see the other six major articles: United States (Overview), United States (Geography), United States (People), United States (Culture), United States (Economy), and United States (Government). II Early Cultural Interaction Print Preview of Section Early American history began in the collision of European, West African, and Native American peoples in North America. Europeans "discovered" America by accident, then created empires out of the conquest of indigenous peoples and the enslavement of Africans. Yet conquest and enslavement were accompanied by centuries of cultural interaction-interaction that spelled disaster for Africans and Native Americans and triumph for Europeans, to be sure, but interaction that transformed all three peoples in the process.

A Native America in 1580 The lands and human societies that European explorers called a New World were in fact very old. During the Ice Ages much of the world's water was bound up in glaciers. Sea level dropped by hundreds of feet, creating a land bridge between Alaska and Siberia. Asians walked across to become the first human inhabitants of the Americas. Precisely when this happened remains unknown, but most scientists believe it occured before 15, 000 years ago. When the last glaciers receded about 10, 000 years ago (thus ending this first great migration to America), ancestors of the Native Americans filled nearly all of the habitable parts of North and South America.

They lived in isolation from the history-and particularly from the diseases-of what became known as the Old World. See also Migration to the Americas. Continue reading article.