The most salient fact about American history is this: the ancestors of everyone who lives in the U.S. originally came from somewhere else. That includes even the Inuits and other Native Americans, whose forebears first crossed from Siberia to Alaska on a land bridge that now lies beneath the icy Bering Sea. From its colonial beginnings, the history of America has largely been the story of how immigrants from the Old World conquered the New. As the historian Carl Wittke noted, eight nationalities were represented on Columbus' first voyage to a continent that eventually received its name from a German mapmaker (Martin Walseemuller) working in a French college, who honored an Italian explorer (Amerigo Vespucci) sailing under the flag of Portugal.
The tide of humanity that has washed over the American continent during the last three or four decades of the 20th century has had profound consequences, to be sure. But in relative terms, it is no match for the waves that came ashore during the 19th. Between Napoleon's defeat at Waterloo in 1815 and the assassination of Austrian Archduke Franz Ferdinand at Sarajevo in 1914, more than 30 million Europeans left their homelands -- some involuntarily -- to settle in the U.S. It was by far the greatest mass movement in human history. The influx continues, in ever greater variety. For people in search of better lives, America remains the ultimate lure.
America's immigration story actually starts in the darkness of prehistory. Archaeologists estimate that Paleo-Indians began their great trek from Asia around 30,000 B.C., in pursuit of shaggy, straight-horned bison (now extinct) and other edible fauna. They gradually moved south and east from Alaska as the glaciers of the Ice Age melted. By 19,000 B.C., the Indians -- a short, hardy people who suffered from arthritis and poor teeth, among other infirmities -- had built primitive homes in cliffs along Cross Creek, a few miles from present-day Pittsburgh, Pennsylvania. One tribal nation, the Cahokia federation, had the sophisticated skills to build a thriving trade center of 40,000 people, across the river from what is now St. Louis, Missouri, between A.D. 1000 and 1250. But by 1300, this metropolis -- the largest on the continent north of Mexico -- had been abandoned, a victim of overdevelopment. The Cahokians had run out of food.
When the first Europeans arrived, the Indian population of North America north of Mexico was about 1 million. According to Ronald Takaki's A Different Mirror: A History of Multicultural America, some Indian sages had forecast the coming of white-skinned aliens. On his deathbed, a chief of New England's Wampanoag tribe said that strange white people would come to crowd out the Indians. As a sign, a great white whale would rise out of the witch pond. The night he died, the whale rose, just as he had predicted. Similar prophecies about predatory whites can be found in the lore of Virginia's Powhatans and the Ojibwa of Minnesota.