Where Is the Great Blue Hole of Belize?

The Great Blue Hole is a nearly perfect circle of deep blue water, approximately 318 metres across and 124 metres deep, surrounded by the shallow turquoise waters of Lighthouse Reef. It formed as a limestone cave during the last ice age when sea levels were much lower; as oceans rose, the cave flooded and its roof collapsed, creating the sinkhole. Jacques Cousteau explored it in 1971 aboard the Calypso, declaring it one of the top five dive sites in the world. At depth, divers encounter massive stalactites and stalagmites — clear evidence of its origins as a dry cave. Analysis of sediment cores from the hole has provided evidence linking severe droughts to the collapse of the Maya civilization. The Blue Hole and surrounding reef were designated a UNESCO World Heritage Site in 1996 as part of the Belize Barrier Reef Reserve System.