Blue Hole (Red Sea)

The Blue Hole is a diving location on the southeast Sinai, a few km north of Dahab, Egypt on the coast of the Red Sea. The Blue Hole is a submarine sinkhole, with a maximum depth within the hole of just over 100 m. There is a shallow opening to the sea around 6m deep, known as "the saddle", and a 26m long tunnel, known as "the Arch", whose ceiling is at a depth of 55m and whose bottom falls away as it reaches the seaward side to about 120m.