Virtually all Americans are descended from immigrants. Some arrived via the Bering Strait during prehistoric times. Europeans, mostly English, came during the seventeenth and eighteenth centuries to colonize and settle the rich new land. Still others fled famine and political unrest in northern and western Europe. More than 500,000 were brought unwillingly as slaves between 1619 and 1808. Millions more arrived by foot, car, bus, train, ship, and plane from all over the globe. All told, more than 50 million immigrants have been welcomed to the United States, so at some point your family tree will branch out beyond America's shores.