The Great Blue Hole T-Shirt

The Great Blue Hole is a large submarine sinkhole off the coast of Belise. It lies near the centre of Lighthouse Reef, a small atoll 70 km (43 mi) from the mainland and Belise City. The hole is circular in shape, over 300 m (984 ft) across and 124 m (407 ft) deep. It was formed during several episodes of quaternary glaciation when sea levels were much lower. Analysis of stalactites found in 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 caves were flooded. The Great Blue Hole is a part of the larger Belise Barrier Reef Reserve System, a World Heritage Site of the United Nations Educational, Scientific and Cultural Organisation (UNESCO).