Why does the Atlantic Ocean have an S-shaped outline?

The S-shaped outline of the Atlantic Ocean is primarily a result of the breakup of the supercontinent Pangea and the subsequent movement of the continents according to the theory of plate tectonics.12

As Pangea began to fragment approximately 180 million years ago, the landmasses of the Western and Eastern hemispheres separated, opening the Atlantic basin. The current shape of the ocean reflects the way these continental coastlines—specifically those of North America and Europe in the north and South America and Africa in the south—fit together like pieces of a puzzle.12

This configuration is further defined by the Mid-Atlantic Ridge, a massive, 10,000-mile-long submarine mountain chain that runs along the north-south axis of the ocean. This ridge marks the boundary where crustal plates are moving apart through seafloor spreading, a process that continues to widen the Atlantic basin today.31