Exploring a GIANT Underwater Sinkhole in Belize!

Coming up, Jonathan explores one of the most famous ocean features in the world, the Great Blue Hole of Belize! Welcome to Jonathan Bird's Blue World! Zach and I have come on an expedition to explore the underwater world of Belize. We're working from the Aggressor 3 liveaboard, which means we stay on this luxury yacht for a whole week, diving 4 to 5 times a day. We've explored some amazing sites, both during the day and at night. We've experienced wonderful visibility and met some curious and interesting creatures on the reefs of Belize. Today we're going to visit the Great Blue Hole, located 40 miles off the coast near Lighthouse Reef. The Great Blue Hole is the largest and most famous ocean blue hole in the world. It's 1,000 feet across, 400 feet deep, and was proclaimed one of the best dive sites in the world by none other than Jacques Cousteau. The Great Blue Hole formed as a cave from erosion during several ice ages in the distant past, when sea levels were lower. Eventually the ceiling of the cave fell in, forming a blue hole. But then as the ice ages came to an end, ocean levels rose, filling it with water and turning a blue hole into an ocean blue hole. We see similar formations today on land. In Mexico and Belize they are called cenotes, but in the Bahamas they are called blue holes. Captain Ken gives us a dive briefing on what to expect. Next it's time to suit up. Jacques and I follow Divemaster Roque over the edge, down the vertical wall of the blue hole. It's 1,000 feet across, so we can't see the other side, and at 400 feet deep, we won't be seeing the bottom either. At about 100 feet, we reach an overhang filled with stalactites. These icicle-looking formations were formed over thousands of years by dripping water when the ocean levels were lower. Back then they would have looked like the stalactites in dry caves do now. But since they are submerged in the ocean, they have marine life such as coral, sponges and algae growing on them. These formations date back as far as 150,000 years, and the largest ones are more than 40 feet long. Down here beyond 100 feet, we don't have much time to explore before we have to turn and head back. Heading back up, I have a look at the life on the wall. There aren't many nooks and crannies for fish. It's mostly some coral and a lot of algae. The shallower we get, the more life there is. At the top, we have a few minutes to make a safety stop, and I have a look at the dense coral reef growing here. As the sea levels rose above the top of the blue hole, coral grew along with it, following the ocean's surface. That's why we can see coral all the way around the blue hole from the air. This healthy reef is home to fish like the French Angelfish and Queen Angelfish, among others. Once we finish our safety stop, we swim across lush seagrass beds to the aggressor. The Great Blue Hole is a world-famous geological formation, which may be too large to truly appreciate from underwater. In my dive, I was only able to see a small part of this immense blue hole in a blue world. Hey everyone! Did you know that you now can become a Blue World member? Hit the JOIN button down below and get access to cool perks like custom badges, early access to new videos, your name in the credits, and more!