Deep refers to any ocean area that has a depth of more than 18,000 feet (5,490 meters). More than 100 deeps have been discovered in ocean floors. Contrary to popular belief, they are not found in the center of the ocean. Most of them are found close to mountainous islands where steep shores plunge down to the bottom of the sea.
The deepest known deep is the Challenger Deep, in the Mariana Trench 200 miles (320 kilometers) southwest of Guam. There, the ocean floor is about 36,070 feet (10,994 meters) below the surface. The Puerto Rico Trench, north of Puerto Rico, has the greatest recorded depth in the Atlantic Ocean. It is about 28,232 feet (8,605 meters) below the ocean’s surface.
