As we all know, everyone in 15th-century Europe thought the world was flat except for one brave and brilliant Italian-born explorer with the inexplicably English name of Christopher Columbus. And as usual, we are all completely wrong.
Not only was a round Earth an accepted fact in Columbus' day, but the ancient Greeks were calculating the size of the spherical Earth back in the 3rd century B.C.E. [source: Stern]. Even better, every ancient sailor who navigated outside of his own bath tub knew that the constellations rose in the sky as you sailed south. And then there's the whole lunar eclipse phenomenon that shows Earth's unmistakably curved shadow.
Columbus wasn't trying to prove Earth was round when he set sail in 1492. He was trying to prove that sailing due west was the quickest way to get to the Far East and the treasured spice ports of India. Not only were his calculations fabulously wrong, but he and his crew would have surely died if they had not accidentally bumped into a cluster of Caribbean islands that Columbus believed to be coastal India. In fact, in all his voyages to the New World, he continued to think he had hit on some part of Asia [source: Royal Museums Greenwich].
One more Columbus factoid: Although Columbus did briefly set foot in Panama on his fourth westward expedition, he never landed anywhere on the North American mainland [source: Royal Museums Greenwich].