Narrator: There's a massive underwater sinkhole off the coast of Belize that extends ... descent to the bottom of the Blue Hole. Their mission was to create a 3D map of the sinkhole's interior ...

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.

The Great Blue Hole is located about 60 miles off the coast of Belize along the Lighthouse Reef Atoll. You can visit the Great Blue Hole with a number of dive services that operate out of Belize ...