The Bermuda Triangle, a loosely defined region bounded by Bermuda, the Bahamas, and Puerto Rico, has been the subject of countless urban legends, from mysteriously disappearing ships to entire World War 2 squadrons. “Typically, you have the bottom of the oceanic crust and then it would be expected to be the mantle,” Frazer told Live Science. This rock then created a raft-like slab that raised the ocean floor by 1,640 feet, as Live Science explains. They analyzed seismic data collected on Bermuda to probe to a depth of about 31 miles below the island territory. Frazer is now probing other islands around the world to see if other similarly unusual structures are lurking elsewhere.