Alfred Wegener first proposed the theory of continental drift in 1915, hypothesizing that around 200 million years ago, all the Earth's land masses were joined together in a single supercontinent called Pangaea. Pangaea began to break apart in the late Triassic period, separating into the supercontinents of Laurasia and Gondwanaland. By the end of the Cretaceous period, the continents had separated into their modern positions.