A seasoned mariner and fearless explorer from Genoa, a major port in northern Italy, Columbus had for years sailed the Mediterranean and North Atlantic, studying ocean currents and wind patterns. Like nearly all navigators of the time, Columbus knew the earth was round. But he drastically underestimated its size. He believed that by sailing westward he could relatively quickly cross the Atlantic and reach Asia. No one in Europe knew that two giant continents existed 3,000 miles to the west.
On October 12,1492, after only thirty-three days of sailing from the Canary Islands, where he had stopped to resupply his three ships, Columbus and his expedition arrived at the Bahamas.
In the following year, 1493, European colonization of the New World began. Columbus returned with seventeen ships and over 1,000 men to explore the area and establish a Spanish outpost.
Before he died in 1506, Columbus made two more voyages to the New World, in 1498 and 1502.

Eric Foner, Give Me Liberty, An American History, 2006, pages 6-7.