>We gear up, buddy check, suck in a few noisy breaths through our regulators and then step off the edge to plunge into the cenote charmingly called Temple of Doom. Instantly we're transported from the surface world of sun and sand — Cancun's high-rise hotels and busy beaches crawling with tourists — into a realm of silent night, moody and mysterious. We've crossed the threshold into the Maya underworld.
>There's a huge subterranean river system spiderwebbing underneath the Yucatan. Hundreds of cenotes — freshwater pools scattered about the jungle with colorful names such as The Pit, Eden and Taj Mahal — are portals into a nether realm that ancient Maya people called Xibalba, literally "place of fear." We've been dreaming of this for years, and the excitement to finally be scuba-spelunking has ignited our senses.
>The guide leads us through a maze of caverns linked together by serpentine passageways. One moment our powerful LED lights bore into Stygian blackness, the next they illuminate stacks of jagged rocks and elegant limestone formations displayed as if in a sculptor's gallery. We're pulled along through the darkness by our fascination, eager to discover what waits around the next corner. All too soon we're back in the first room, staring upward in awe at the brightness pouring down through natural windows in the cavern's ceiling. A lifetime of diving on coral reefs cannot prepare you for this. It's totally and refreshingly different.
>Dozens of cenotes along the Riviera Maya between Cancun and Tulum, including the popular Dos Ojos site, have galleries richly decorated with luminous columns, monolithic pillars rising floor to ceiling. Some structures are convoluted with oozing shapes resembling gigantic melting ice cream cones. There are countless shadowy chambers dripping with menacing stalactites. Gran Cenote has formations that look just like the teeth of a massive shark conjured from a nightmare. Car Wash has a stand of beautiful lily pads, and its entrance is choked with an artful tangle of tree branches.
>At Chac Mool we descended immediately into the hazy murk of a halocline, the transition from lighter freshwater on top to denser saltwater below. Parts of our bodies seem to disappear from sight for a moment in the blurry, swirling water, but they snap back into razor-sharp focus the next. It's fascinating but a bit disorienting, too. Eventually we break through the "wormy water" into stunning visibility. Our journey has been perfectly timed for a light show; hovering under a skylight, we are bathed in sunrays that have filtered through the jungle foliage above. The sun's brilliance is transformed into liquid luminance right before our eyes: Beams and curtains lance downward, shimmering spotlights dancing on a subterranean stage. The effect is hypnotic.
>Our lights cut through black mystery to reveal subtle beauty, brush strokes in a remarkable landscape. We're in a cathedral-like chamber, stately and spacious. Ledges and recesses line the walls, and it feels as if someone or something is watching us from the shadows, which shift and bend. Limestone stalactites hang above, a cluster of needle-sharp spears that bring to mind a crystal chandelier, exquisite and otherworldly. The room's floor, a heap of bright alabaster slabs apparently discarded by a giant stonemason, is aglow. A weighty eeriness swirls around me for a moment, and then peacefulness descends on me like a warm, heavy cloak. I reverently ooh and aah, suspended in the middle of it all. An electric-blue light beckons me upward, and I levitate through gin-clear water to slowly break the surface next to my companions.
>Removing our regulators, we breathe in the damp, cool air. We're floating in an air pocket. The sky here is not blue; above our heads is rock and dirt and a jumble of tree roots. To our amazement, fossilized seashells — clams and the graceful whorls of a large marine snail — poke out from the ceiling, proof of a past connection to the ocean.
>We are above water but under ground. We drift between two times; our bodies are stretched between two worlds. To return to Earth, we must first descend into water, then retrace our fin-steps through Xibalba in darkness — back to the light streaming through the cenote portal. I look forward to the journey.
>CONDITIONS: The Riviera Maya's cenotes provide great diving all year round. Water temperature is 77°F. There are no open-ocean conditions (swell, surge, waves or wind) to worry about, of course. Current is also a nonissue in the majority of cenotes. Visibility is usually superb, except when careless divers stir up silt. Most cenotes are no deeper than 40 feet.
>HOW TO DIVE IT
>MORE INFO: Rivieramaya.com
>Tulum's Topside Attractions
>© Alert Diver — Spring 2014