An eruption near the Mid-Atlantic Ridge began the formation of a volcano nearly 110 million years ago. It grew large enough to create a series of ridge islands, but the movement of the plates carried the volcano away from the ridge and onto the ocean floor. After traveling 500 miles in 30 million years, the volcano and its islands had sunk below the surface… to exactly the right depth for coral reef formation! Fringe reefs evolved into barrier reefs, which turned into the present-day atoll. Everything that made it above sea level is now the British overseas territory known as Bermuda.