Columbus Discovered America

It is possible that Africans discovered South America before Columbus. It is certain the Viking discovered North America before Columbus. But only Columbus truly discovered the New World.

None of the Vikings, none of the Africans, not a single person prior to Columbus, successfully incorporated the knowledge of the Americas into the culture from which they came.

If you stumble over a chair in the dark, you haven't discovered a chair. You just figured out a new way to stub your toe.

Columbus stumbled over the chair in the dark, figured out that it was a chair, communicated to the rest of the world that chairs existed, and then incorporated into his own culture a new culture that used chairs as a matter of course. Columbus discovered the New World. Everyone else just stubbed their toes in the dark.