Called « Dragon’s blue hole » or « eye » by local fishermen, this underwater gulf is probably the deepest hole of the world, reaching 300 meters deep. The previous record tenant was the Dean’s blue hole, Bahamas, reaching 202 meters.
Sansha Yongle Blue Hole
Located in Paracel Islands in the South China Sea, The Sansha Yongle Blue Hole has always fascinated people, whether they were locals or travellers. In August 2015, researchers used an underwater robot to launch a serie of explorations around this blue hole. They found out that the hole was a sanctuary for twenty or so fish species that essentially live in the shallow part. Indeed, most of the time, the water flow of a blue hole is very bad and it makes living growth impossible in deep waters.
What are the world’s most famous blue holes?
The blue holes or underwater excavations caves, sinkholes, cenotes is a very common fact, indeed, there is an extraodinaire concentration of them in the Andros Islands, Carribean, where we can already list 178 sea blue holes.
This hole that was considered as the biggest for years has a circular shape at the surface. The diameter of its surface changes from 25 to 35 meters width, then it goes larger at 20 meters deep to become a hundred of meters width cave.
With its almost perfect circular shape, this blue hole is an exceptionel spot for underwater photographers. It has a 300 meters width diameter and a 124 meters depth that have fascinated numbers of adventurers, like Jacques-Yves Cousteau who established a depth map of the place. This spot is described as one of the 10 most beautiful dive spots of the world.
This approximatively 130 meters deep blue hole became the Mecca of hundreds of freedivers from all around the world who come there to practice. This dive spot located in Dahab, Egypt, is famous for its dangerous nature. Indeed, every year several deaths are recorded among the divers that try to cross the tunnel linking the hole to the sea.
Located on the west coast of the island of Gozo, Malta, the blue hole of Gozo is way less impressive than the ones listed above. However, it is still very appreciated by divers thanks to its beautiful rock formations and abundant marine life, especially the strong presence of invertebrate. These elements make it being considered as one of the best dive spots of Malta.
What exactly is a blue hole?
Blue holes appeared during the last ice age when the level of the sea was 100 meters lower than it is today. The creation of these blue holes is due to the chemical deterioration of limestone caused by the streaming of rain water that the plants first made acid. The water then penetrates the ground and erodes everything, creating at the same time large underground hollows. After years, the ceiling will fall in and the sea will rush into the hole, giving it the appearance we now know.