Dean's Blue Hole dips some 663 feet (203 meters) into the ocean floor right off shore. It is said to be the deepest blue hole in the world, and the second largest underwater chamber. It is located west of Clarence Town on Long Island, and is also the site where the Freediving World Record was set in April 2007.Experts at Reeldivers and Vertical Blue who have done dives at the site report that: ,It is enclosed on three sides by a natural rock amphitheatre, and on the fourth side by a turquoise lagoon and powder white beach. There is never any swell or waves inside the Hole, and visibility is usually between 50 - 100 feet (15 - 30m). At the surface the Blue Hole is 80 x 120 feet (25 x 35m), but opens out after 60 feet (20m) into a cavern with a diameter of at least 330 feet (100m).,