Today, we know that Earth’s land masses are divided up into seven continents. Not long ago, most scientists presumed that these continents—Earth’s crust—were permanently fixed on the outer layers of the globe. But in 1912, scientist Alfred Wegener theorised that these continents were actually all once joined together, then broke apart, and are now slowly drifting across the Earth! He noticed that all of Earth’s present-day continents seemed to fit together like a jigsaw: not only did the land masses correlate, but he also found clues amongst the world’s plants, animals, rocks and mountains that indicated they were all once found together on a supercontinent called Pangaea. Today this Continental Drift Theory—and how it gave rise to landforms like the Western Ghats—is generally accepted, but it was highly controversial at the time!