The Great Blue Hole is a large, circular sinkhole located in the Caribbean Sea off the coast of Belize. It is approximately 1,000 feet across and over 400 feet deep, making it one of the largest underwater sinkholes in the world. The Great Blue Hole is famous for its vibrant blue color, which is created by the deep, clear water and the sunlight reflecting off the white limestone walls.

The Great Blue Hole is a popular destination for divers, as it is home to an incredible variety of marine life, including many species of reef fish, sharks, and manta rays. The clear, still water provides excellent visibility, making it a popular spot for both recreational and technical divers.

The Great Blue Hole was designated as a UNESCO World Heritage Site in 2018 as part of the Belize Barrier Reef Reserve System. In addition to its beauty and ecological importance, the Great Blue Hole is also a popular spot for scientific research, as its unique geology provides valuable insights into the formation of underwater sinkholes and the evolution of coral reefs.