The cleft in the mountain wall is hung with plaques to the deceased, most of whom perished in their late 20s. Locals never fail to remind you, either, that those fatalities were also highly experienced divers. As if to taunt, the Red Sea slaps in a rhythmic froth against the rocky shoreline just beneath me. Even from here I can view the immense sinkhole's blue-gem depths, circumscribed by a rictus of pale, reefy turquoise. This is the infamous Blue Hole of Dahab, Egypt. Granted, I'm only snorkeling today, but I can't help but feel a vague, tidal pull of fear in my gut. Locals estimate the death toll at the Blue Hole to be anywhere from 130 to 200, making it the most dangerous dive site in the world. And while visitors often hear about nitrogen narcosis, a drunken-like state of consciousness induced by inhaling pressurized gases, no one really knows what happens to those ill-fated divers who fade into the sinkhole and never resurface. I splash gracelessly into the polar water and am immediately mesmerized by the narrow corridor of impacted, maroon boulders, refracted sunlight, and the first poly-chrome tassels of reef. We hang a right over a shoal saddle and coast along the reef's ridge. Despite the fleshy folds of bright coral, and the acrylic roiling of so many fish, the Blue Hole's real attraction for divers is a submerged arch. Diver beware though, because this siren formation begins at 55 meters down, and is the site of the hole's numerous deaths. According to my hotelier, Jimmy the Legant (a misspelling of Legend), the real reason people die down there is pure hubris. "As we are human, we are a bit greedy, we always like to do a bit coo coo action..." he muses. "Challenge, it's a great thing, but if you are not ready, not a good thing." A self-proclaimed Dahab celebrity, Jimmy is a study in creams, always donning a canvas fisherman's hat, khaki barn jacket, and ecru slacks. He rides his bike though Dahab's crowded beachfront "cruising for a bruising," which he explains to me one day after nearly plowing through me. I meditate on his words while floating above the precipitous coral drop-off fringing the Blue Hole. I am uneasily aware of the lunar-blue abyss beside me, the barnacled ossuary I drift over in an aureole of wavering sunlight. Jimmy has descended 30 meters into it, and describes the feeling as flying in the sky. It's an image that offers some insight into the euphoria many divers must chase below. Still, at what price? I wonder what really is at stake for these young divers, and try to fathom the arch's sunken dimensions, or the strange light that emanates from its vault. Indeed, many divers perish because they are disoriented by this pallid, blue glow. Others, like ill-famed Yuri Lipski, succumb to nitrogen narcosis. In 2000, the 22-year-old Russian-Israeli dive instructor descended rapidly into the Blue Hole and drowned in a foggy cloud of kicked-up sand, all recorded on his dive-camera over seven minutes. Whenever I broach the subject with Jimmy, his voice trails with disappointment, and he rambles sourly about things like overweight equipment and accelerated descents, about hubris... I resurface momentarily to a familiar view of the wind-tossed mountains that rumble across the Sinai Peninsula. In Jimmy the Legant's grand cosmology, anything in life is recoverable except for a Self, and we must therefore make peace with that Self: "I have a lot of things missing, but I have one thing that is mine," he says. "It is myself. I'm not rich, but I'm healthy." Jimmy's meditations strike me as another incarnation of that ancient Mediterranean adage: Know Thyself. Perhaps it's the absence of such personal insight that lures divers like Yuri Lipski to sink 300 feet into a world of cold, subaqueous darkness to receive the ultimate revelation. Assuming, of course, that Jimmy's accusations of "coo-coo" hubris are well-founded. I choose to skim over the Blue Hole and admire the shallower climes. I can't say I've achieved Jimmy's beachy zen, but I know some of my limits. The barnacled arch crouching far beneath holds no draw for me.