The Arch

The element that makes this Blue Hole notoriously dangerous is its very structure which the professionals term as “The Arch.” The Arch is simply a tunnel under the reef that links the Blue Hole to the Red Sea, on the opposite side. While there is no thick layer of nitrogen sulfide in the depths of the Blue Hole of Sinai. Having said that, there’s an invisible presence in this sinkhole that disorients divers. The phenomenon is known as nitrogen narcosis and it creates altering effects of depth on the diver’s consciousness.