They were rolling in the deep. Scientists have identified what could potentially be the “deepest known blue hole” in the world, extending so far down that the bottom has not yet been reached.

Like a pinprick piercing the azure Caribbean Sea, the Great Blue Hole is as mysterious as it is mesmerizing. From above, this almost perfectly circular underwater sinkhole is a deep, dark bullseye ...

A water-filled natural limestone cavern, Dean's Blue Hole plunges 663 feet below ground level on Long Island, part of a string of Bahamian islands south of Nassau and New Providence Island.