Narrator: A long time ago, people thought the world was flat, and if you sailed uncharted waters, you might just fall over the edge into space. Now this may seem strange to us now, but in those days, no one knew what lay over the far horizon. But with pirates and hurricanes and sea monsters to contend with, it was a very dangerous voyage. But in 1492, there appeared an Italian navigator, a man with a revolutionary idea: He thought the world was... square. And his name was... Christopher Columbus.