Caves and blue springs dot the cactus-covered plains of east-central Mexico. Here the rivers flow underground, gathering heat and minerals, gouging tunnels under the desert. Above the teeming aquifer, a flat, rocky scrub stretches from the El Abra Mountains to the Gulf of Mexico, 30 miles to the east. Home to snakes, scorpions and a few scraggly cows, the plain is baked by the sun and blasted by "el viento del norte," a hot northern wind that comes often. When it comes, it lingers for days.
April 6, 1994
At high noon the wind rages. I stand with a handful of reporters and ranchers above an enormous water-filled sinkhole called Zacatón. We stare down 70 feet at the warm thermal spring. White plumes of sulfur swirl through the water like milk. We walk the perimeter of the hole, straining for a glimpse of two men who should soon rise from setting a world scuba depth record, achieved in absolute darkness 1,000 feet below the water's surface.
The hot wind snatches hats from our heads and words from our mouths. Bright circles of floating saw grass, 10 to 30 feet in diameter, bounce across the water like slow-motion billiard balls. I try to comprehend the spring's impossible depth. If the Empire State Building sank to the bottom, I could step onto its main observation deck from where I stand.
Somewhere down in the water is Sheck Exley, a high school calculus teacher and karate expert from Live Oak, Fla. Exley, 45, is also the undisputed master of deep scuba, which is practiced mostly in cave pools. He has logged more than 3,000 successful cave dives, far more than anyone else. It is Axley's own depth record of 867 feet, set in another Mexican spring in 1989, that he and a colleague, Jim Bowden, set out to break this morning.
Bowden is a 52-year-old adventurer and dive instructor from Austin, Texas. Five years ago he discovered Zacatón after more than a decade spent searching the springs and caves of Mexico and Central America for places where no human had been. Under Exley's tutelage, Bowden trained for the past year for this dive. He poured thousands of dollars into the equipment needed to make a record descent. He recovered from a case of the bends—suffered on a training dive at Zacatón in November—that would have retired, if not killed, other cave divers.
Closer to the surface, yet hidden from us by the suspended sulfur, three support divers hover, waiting to assist Exley and Bowden in an anticipated 10-hour decompression. A 1,000-foot descent packs nitrogen into a diver's blood like bubbles in beer; rising too fast would rip his joints and muscles. The hours of slow ascent, while they breathe exact mixtures of oxygen, helium and nitrogen at prescribed levels, will let the divers properly outgas, or shed, the excess nitrogen.
Parallel ropes, 25 feet apart, are tied to rocks at the water's edge. They dangle halfway down the flooded pit, holding in their places more than two dozen dive tanks from which Bowden and Exley will breathe on their way back to air. Two hours ago the explorers had entered the sinkhole by swimming through a 600-foot-long cave, thus avoiding a difficult rappel down the cliff face. Hidden 30 feet below the floating grass, this natural tunnel carries currents that rise from the depths of Zacatón and spill out from a nearby spring.
When at last two of the support divers surface, the wind gusts so that none of us above can hear what they say. But we can see. We can see a woman in a wet suit grabbing the shoulders of another woman, holding her, placating her. We can see bubbles, as regular as breath, plopping up near one of the ropes. We can see the other rope hanging in water that is chillingly still.
The sun beats down. The hot wind blows. The third support diver surfaces to join the other two. Beside them, bubbles rise from one line only.