Columbus set out to reach Asia by a direct sea route. His calculation was wrong: he estimated the Earth's circumference much smaller than it actually was. But this error carried him, in the autumn of 1492 with three ships — Santa María, Pinta, Niña — west across the Atlantic to an island in the Bahamas. He believed to the end of his life that he had reached India, and so called the region's peoples 'Indios' — a misnaming that would persist for centuries.

What Europeans did in the Americas after 1492 ranks among the founding conflicts of the modern world. Spain rapidly conquered the Caribbean, then Mexico and Peru; the Aztec and Inca empires collapsed. The Indigenous population declined by roughly 80–90% across the 16th century, driven by introduced diseases (smallpox above all), war, and forced labour — one of the largest demographic collapses in human history.

The biological and cultural flow known as the 'Columbian Exchange' permanently reshaped both continents: tomatoes, potatoes, maize, cacao, and tobacco moved east; wheat, horses, cattle, sugar cane, and disease moved west. The Atlantic triangular trade took shape, with enslaved Africans forcibly transported to underwrite American plantation agriculture, and European capitalism rose on the back of this colonial system. Columbus's personal memory is contested today; the historical scale of what his voyage set in motion is not.