Analysis of stalactites found in the Great Blue Hole shows that formation took place thousands years ago. As the ocean began to rise again, the cave was flooded.
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 the world’s largest sinkhole, measuring an incredible 300 meters across and roughly 125 meters deep. It was formed during several episodes of quaternary glaciation when sea levels were much lower.
This site was made famous by Jacques Cousteau, who declared it one of the top five scuba diving sites in the world. In 1971 he brought his ship, the Calypso, to the hole to chart its depths.