Blue Hole (Red Sea)
One of the worlds most famous diving locations is the Blue Hole, located on east Sinai, north of Dahab in Egypt. The Blue Hole is a tunnel opening out to the sea, 26m long. The top of this tunnel is located at a depth of 56m.
Blue Hole is a very difficult dive, you have to stay within your limits. The dim light and the temptation to the dive down to the arch leads very often to nitrogen narcosis.