For millennia, almost all Europeans were found in Europe, few Africans existed outside Africa, and Asians lived, nearly without exception, in Asia alone. No one in the Eastern Hemisphere in 1492, so far as is known, had ever seen an American native. (Some researchers believe that English fishing vessels crossed the Atlantic a few decades before Colón, but the principle holds—one didn’t find communities of Europeans or Africans in Asia or the Americas.) Colón’s voyages inaugurated an unprecedented reshuffling of Homo sapiens: the human wing of the Columbian Exchange.
