Great Blue Hole

From Wikipedia, the free encyclopedia

The Great Blue Hole, located near Ambergris Caye, Belize.

The Great Blue Hole is a large underwater sinkhole off of the coast of Belize. It lies at near center of Lighthouse Reef, a small atoll 60 miles from the mainland and Belize City. The hole is almost perfectly circular, over 1,000 feet across and 400 feet deep. It was formed as a limestone cave system during the last ice age when sea levels were much lower. As the ocean began to rise again the caves flooded, and the roof collapsed.

[edit] Diving

The Great Blue Hole is of interest to divers, although because of the near vertical (past vertical in some cases) walls and great depth, the interior of the hole is of little interest. What divers come for are the walls themselves. Ringing the walls of the hole, beginning at around 100 feet, the sheer face of the hole becomes a hanging curtain of stalactites, some up to 40 feet long. Divers can swim among these, provided they are very careful to control their depth. Farther down, in the domain of technical divers (110 feet or deeper), the ancient cave systems opens up, leading to many smaller passages.

The Great Blue Hole is highly frequented by bull sharks, therefore making a dive a potentially dangerous endeavor. While no cases of (fatal) attacks on humans have been reported, divers should be aware of this at all times and retreat when groups of them appear.

[edit] Discovery

This site was made famous by Jacques-Yves Cousteau who declared it one of the top ten scuba diving sites in the world. In 1971 he brought his ship, the Calypso to the hole to chart its depths.