The Great Blue Hole is a giant marine sinkhole off the coast of Belize. It lies near the center of Lighthouse Reef, a small atoll 70 km from the mainland and Belize City. The hole is circular in shape, 318 m across and 124 m deep. It has a surface area of 70,650 square meters.

The Great Blue Hole was formed during several episodes of quaternary glaciation when sea levels were much lower. Analysis of stalactites found in the Great Blue Hole shows that formation took place 153,000, 66,000, 60,000, and 15,000 years ago. As the ocean began to rise again, the cave was flooded. The Great Blue Hole is a part of the larger Belize Barrier Reef Reserve System, a UNESCO World Heritage Site.

Underneath the surface of the Belize Blue Hole, the explorers found evidence of a hollow interior filled with stalactites and stalagmites. These stalactites acted as veritable proof for the explorers to conclude that the Hole was a swallow hole.

Water levels in the surrounding areas of the sinkhole are so shallow that the coral often breaks the surface at low tide. The watercolor of the swallow hole is deep blue in contrast with the aquamarine color of the water neighboring it.

In addition to the crystal clear water that tempts divers, the reef surrounding the Hole is home to many exotic fishes like the nurse tip shark, reef shark native to the Caribbean, and various other marine creatures.

The moderate temperatures of the country allow potential divers to penetrate the depths of the Belize Hole all year round. Likewise, the complete absence of water currents and acute temperature changes in the swallow hole allows divers to try and make a foray all year round.

The Hole has got a great fan following in the world, and the Belize locals have a keen desire to have the Hole anointed with the title of being one of the world’s seven wonders. The Discovery Channel, in 2012, announced the Great Blue Hole as number one on its list of “The 10 Amazing Places on Earth”.