Dean's Blue Hole is the world's deepest known blue hole with seawater. It plunges 202 metres (663 ft) in a bay west of Clarence Town on Long Island, Bahamas. The full depth of the cave was reached by Jim King in 1992.
In April 2010, William Trubridge broke a free-diving world record in the blue hole reaching a depth of 92 metres (302 ft) without the use of fins (Constant Weight...