The Great Blue Hole, located off the coast of Belize, belongs on the Bucket List of anyone who loves scuba diving, or who simply loves the ocean in general — after all, this magnificent natural formation looks great seen above the surface of the water. According to the local resort Chabil Mar, the Great Blue Hole, also known as the Belize Blue Hole, which is found 62 miles off the coast, is an underwater wonder. It's an impressive 984 feet in diameter at its widest point and is more than 350 feet deep.
All the more impressive is the fact that, for tens of thousands of years, this deep "hole" was entirely above the water and was in fact a dry cave. According to Business Insider, the cave was only filled with water some 14,000 years ago as glaciers melted and ice sheets retreated, causing sea levels to rise at the end of the last ice age. Thus, exploration of the interior of the Blue Hole reveals stunning geological formations that can only happen in the dry conditions of a cave: stalactites and stalagmites. Some are small, some are dozens of feet long.
Also found at the bottom of the Great Blue Hole are a surprising amount of dead sea creatures. About 285 feet below the sea's surface, divers detected a layer of hydrogen sulfide spanning the width of the hole, and below that toxic strata is water nearly devoid of dissolved oxygen. So any animal, like conchs or crabs, that slipped below the hydrogen sulfide would suffocate and die.
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