What giant sinkhole off the coast of Belize is a famous scuba diving site?

The giant sinkhole off Belize’s coast famous for scuba diving is the Great Blue Hole.

The Great Blue Hole is a nearly circular marine sinkhole at the centre of Lighthouse Reef, an atoll about 70 kilometres from Belize City. It is approximately 318 metres across and 124 metres deep, making its intense blue colour visible from above. The flooded limestone formation developed through several stages during past ice ages, when sea levels were much lower and the site was a dry cave system.

Evidence of its earlier formation above sea level includes submerged stalactites. As glaciers melted and oceans rose, the cave was inundated. The hole is now part of Belize’s Barrier Reef Reserve System, a UNESCO World Heritage Site.

Ocean explorer Jacques Cousteau made the site internationally famous after bringing the Calypso there in 1971 to chart its depths. The Great Blue Hole is distinct from the Blue Hole at Dahab, Dean’s Blue Hole in the Bahamas, and Dragon Hole in the South China Sea.