About 200 million years ago, all the continents on the Earth were actually one huge "supercontinent" surrounded by one enormous ocean. This gigantic continent, called Pangaea , slowly broke apart and spread out to form the continents we know today. Sound amazing? Believe it or not, the continents have come together and spread apart at least three times before. After all, our planet is 4.5 billion years old. On that time scale, 200 million years ago isn't such a long time! What can make the continents move? Plate Tectonics! Scientists have found many kinds of evidence that support this idea. Here are just a few: • The shapes of continents fit together like a puzzle. Just look at the east coast of South America and the west coast of Africa—it's almost a perfect fit! • Identical rocks have been found on different continents. These rocks formed millions of years ago, before the continents separated. They formed from the same minerals and under the same conditions. • Fossils of the same kinds of dinosaurs, Mesosaurus, have been found in South America and Africa. These dinosaurs roamed the Earth before the two continents broke apart.