Scientists are about to explore a mysterious 'blue hole' in the ocean

Researchers are setting out to explore one of the ocean's greatest mysteries: A type of sinkhole in the ocean floor known as a "blue hole." Blue holes are huge caverns beneath the seafloor that are carved out by some unknown force, though scientists believe there may be freshwater springs within them. The expedition is being funded by NOAA. It's been said that we know more about space than we do about what lurks in the deepest reaches of Earth's oceans. The appearance of mysterious "blue holes" ...