The Blue Hole, Egypt

Like how a flame pulls in a moth, the Blue Hole in Egypt calls out to divers. What drives people to seek deep, underwater caverns where the sun’s rays don’t reach? It is probably the desire to explore or the boasting rights, but the 394-foot-deep underwater abyss is no stroll in the park, even for the most daring divers.

The azure sinkhole looks beckoning, but even a seasoned explorer will find it risky. Past depths of a hundred meters, nitrogen narcosis sets in like a drunken stupor. This fogginess is beyond the worst hangover- one from which you may never recover. Caution: the Blue Hole is not a watering hole.