Depths of Belize's Great Blue Hole, the World's Largest Sinkhole, to Be Explored by Submarine

At a Glance

• The depths of Belize's Great Blue Hole are about to be explored for the first time.
• The UNESCO World Heritage Site is the largest sinkhole in the world.
• Global entrepreneur Richard Branson and Fabien Cousteau will be exploring the sinkhole.

Belize's Great Blue Hole is one of the most awe-inspiring yet mysterious places on the planet, stretching over 1,000 feet across, more than 400 feet deep and standing out as a bold blue blob amid the light blue waters of Lighthouse Reef. And now, for the first time, we're going to find out what it looks like below the surface.

Global entrepreneur Richard Branson and Fabien Cousteau — grandson of Jacques Cousteau, who took a one-man submarine into the Great Blue Hole in 1972, according to the USGS — will take a submarine to the depths of the sinkhole on Dec. 2 to explore part of the Earth that's never been seen before.

The underwater sinkhole sits some 60 miles off the coast of Belize City and is part of the Belize Barrier Reef Reserve System, a UNESCO World Heritage Site.

(MORE: New Zealand Islands Inching Closer Together After Monstrous Earthquake)

For the first time, the depths of Belize's Great Blue Hole will be explored by Richard Branson and Fabien Cousteau.

(Seann McAuliffe/Flickr)

The circular sinkhole was once a cave system that resided at sea level hundreds of thousands of years ago, NASA scientist Glyn Collinson told Belize.com. Over time, rising seas overtook the configuration, flooding and soon collapsing it into the 400-foot-deep chasm it is today.

Since its discovery, the Great Blue Hole has been a popular site for scuba divers around the world, but divers can only venture about 130 feet below the surface — not even halfway to the full depth of the sinkhole.

Branson and Cousteau's exploration will provide the first measurements of the site since scientists used sonar to map it in 1997, according to the Telegraph. Using a Stingray 500 built by Aquatica Submarines, the upcoming exploration will be by far the most thorough exploration of the marine sinkhole.

"We're not even going to set down on the bottom because it's theoretically been filling with silt for the last 100,000 years," Aquatica's Chief Pilot Erika Bergman told Engadget. "We can get really, really nice and close up to the objects without touching them or stressing them in any way. We've had a lot of experience doing that around shipwrecks, mostly, where you definitely don't want to touch anything."

Part of the exploration will be available to view via livestream or TV broadcast, both provided by the Discovery Channel.

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