Narrator: There's a massive underwater sinkhole off the coast of Belize that extends 125 meters into the Earth's crust. It's called the Great Blue Hole. Scuba divers and snorkelers have been ...

The Great Blue Hole is a massive marine sinkhole in the Caribbean, situated off the coast of Belize. Its diameter is 1,043 feet, and its depth reaches 407 feet.

And so, when Richard Branson and a team of scientists took a submersible down to the bottom of Belize’s iconic Giant Blue Hole, they were braced for some truly extraordinary sights. The Blue ...