A brave guy how is called Dauntless freediver Guillaume Néry has dived in "Dean's Blue Hole". The long of this hole is a 202 meter (663 ft.) which is located on Long Island, Bahamas.
A blue hole is considered as an an underwater sinkhole, and it is known as the deepest known salter water blue hole in the world. It's diameter of roughly 25 to 35 meters (82–115 ft) – at its floor, the diameter expands to a whopping 100 metres (330 ft), almost quadrupling in size. This hole attracts many people to discover it. This video shows you the most experience ever.
Watch the video here