On the remote island of Long Island, Bahamas, just a few steps off the beach lies a 663-foot deep underwater cavern known as Deans Blue Hole, considered to be the world’s deepest saltwater “blue hole” – a term used to reference any deep, water-filled sinkhole with an entrance below the water surface.
What makes Dean’s Blue hole exceptional is its’ depth, while most sinkholes and blue holes reach a maximum depth of 110 meters, Dean’s Blue Hole plunges to more than 200 meters making it the world’s best free diving location. From eye level, it may not look like much with its’ circular surface diameter of 30 meters, but underneath after descending 20 meters, the hole widens into a 100-meter diameter cavern.
Blue holes get their name from the dramatic contrast between the dark blue, deep waters of their depths and the shades of lighter blue surrounding them. The acute blue color is generated by the high transparency of water and the bright white carbonate sand. The spectrum of colors, blue, yellow, red, and green, are absorbed during their way through the water. Only the blue light manages to reach the white sand and reflect back.
It’s speculated that blue holes were formed during the ice ages when sea level was significantly lower than the present. When deep groundwater gradually dissolved the limestone over time until the ceiling of these voids collapsed, which were then filled with water when the sea levels rose.
Tourists from all over the world flock to Dean’s Blue Hole, but the locals stay away. They believe the mysterious blue hole was dug by the devil. Generations after generations have never visited the local attraction as they are too scared, they know it would lead to death. They say if they were to approach it, even floating above the water, it would pull them down, as the devil might.