Alfred Wegener was the first person to officially come up with a hypothesis about the continental drift. Even though he did not get a lot of support, Wegener was persistent and managed to find several clues that were supporting his hypothesis.
One of the clues was that the landmasses of South America and Africa were an almost perfect match. More specifically, he was referring to the eastern coastline of South America, and the western coastline of Africa.
On the image that is shown, it is far western part of South America, and the coastline of the Gulf of Guinea in Africa.
While he still didn't had an evidence for it, and it was only an assumption, over time it turned out that Wegener was right. Many evidence came out on the surface and confirmed that South America and Africa were once part of a single landmass, initially of Pangaea, and later of Gondwanaland, before they split.
