Bermuda may well be associated with exaggerated stories of missing ships and planes, but there is another mystery about this part of the Atlantic that has been puzzling scientists for decades: Why does the island appear to float above the surrounding ocean? A new study published in the journal Geophysical Research Letters could have the answer. Researchers have discovered a massive 12.4-mile (20-kilometer) thick layer of rock beneath Bermuda between Earth's crust and mantle.