Great Blue Hole

The Great Blue Hole is a circular marine sinkhole roughly 300 metres in diameter and 125 metres deep located at the centre of Lighthouse Reef Atoll off the coast of Belize. The dark indigo circle surrounded by pale turquoise shallows is one of the most recognisable dive sites on earth and was popularised globally by Jacques Cousteau. Beneath the lip of the cave system, massive stalactites hang from submerged overhangs, confirming the structure formed as a dry cave during the last glacial period.