chamber Atlantis — Deep within Lechuguilla Cave, these shelfstone "tables" formed at an old water level in the chamber known as Atlantis.
© WGBH Educational Foundation

We shifted positions, shuffling strips of foam padding that cushioned and insulated us from the cold hard earth. The cave's constant humidity, which had kept us sweating for hours as we made our difficult way down, now leached away warmth. We stank of the day's work, our funk blending with Lech's peculiar soil-and-metal odor. If I had thought about it then, I would have attributed the cave's unique smell to traces of sulfur.

At ten the previous morning, we had somehow coaxed a rented Oldsmobile down the rugged "four-wheel drive only" road to an unmarked parking area, where we geared up beneath a cloudless June sky. From there we had made the two-mile desert hike to the entrance in shorts, T-shirts, and boots. Our crossing spooked a small herd of deer. I paused to watch them scatter over a rise, leaping through a cluster of the prickly lechuguilla bushes for which the cave was named. Low rocky hills dominated the landscape.

These sun-blasted ridges and the rock below them had been alive 250 million years ago. A magnificent barrier reef geologists call El Capitán had stretched for over 100 miles along the coast of a shallow inland sea that once covered the American Southwest. The living reef had died as the basin it enclosed grew too salty. Then, long buried under later deposits, the dead reef became limestone, the ideal stone for caves.

A natural collapse just inside the entrance pit had blocked Lechuguilla for thousands of years, until cavers dug through it on Memorial Day 1986. The miles of passage beyond had revealed no trace of humanity or, for that matter, bats or other traditional cave life. A few cave crickets inhabited the upper passages, but even they became scarce below the rappel into Glacier Bay. Lech was a truly virgin place, rare in the annals of human exploration.

El Capitan — Lechuguilla lies within this ancient coral-reef-turned-mountain range, the Guadelupe Mountains, which straddle the Texas-New Mexico border. Here, the Texas peak known as El Capití¡n.
© WGBH Educational Foundation

Down into darkness

Lechuguilla's entrance was a rectangular hole 70 feet deep and wide enough to swallow a truck. We had donned helmets, kneepads, and climbing harnesses, then had taken one last look at daylight before clipping into the rope. It felt odd to begin a long descent without nylon overalls. Made of the same ballistic fabric as police vests, they had always been my preferred garb for climbing in cooler climes. But coveralls would have been unbearable in this warm cave. My bare arms and legs, now tucked into synthetic underwear for sleeping, were caked with soil, sweat, and blood from inevitable encounters with sharp rocks, along with gritty bits of white aragonite that we had acquired while squeezing through a tight formation-lined tube.

From the entrance, we had descended a series of climbs, stoop walks, and free-hanging rappels—the longest of them from an undercut cliff 145 feet above the dark floor—until we had reached the stadium-sized chamber of Glacier Bay. A natural avenue wound through the tilted space, ending in an area of tricky crawls and rope traverses at the Rift, a multilevel fissure 200 feet deep. We snaked through the Rift to the Overpass, which had opened up most of the known passage just the year before. Our guide said the cave didn't really begin until you had climbed, hiked, slithered, and rappeled from this point to the shore of Lake Lebarge, over 700 feet down.

Lebarge, a shallow, clear pond perhaps 75 feet in diameter, straddled the first of a series of huge passages that glistened with surrounding white gypsum in a myriad of forms: crystals, flakes, flowers, spikes, cones, and powder. Other lakes followed in the Lebarge Borehole, some of them lined with bulbous, milky mounds of calcite unlike any cave formation I had ever seen. In some places, rows of ghostly human-sized forms called "hoodoos" stood like sentries along the path. These were built of countless thin mineral flakes that had floated on the surface film of long-vanished pools, each accumulating mass over months or years or decades until it became heavy enough to sink in the still water and another began growing in its place. When the water retreated, the hoodoos remained.

A stunning variety of cave formations decorate the edge of Lake Lebarge.
© WGBH Educational Foundation

Eaten by acid

The massive gypsum deposits lining Lechuguilla's limestone walls had suggested to some geologists that its tunnels were carved not by runoff flowing from the surface—as was long considered the case with all limestone caves—but by strong chemical reactions between ancient groundwater and hydrogen sulfide rising from a deep subterranean source. Hydrogen sulfide associated with petroleum deposits in the rich Delaware Basin field was believed to have been chemically converted to sulfuric acid, which could eat into limestone like gasoline poured into a styrofoam cup. In the early 1980s, few in the geological establishment had accepted this theory, originally applied to Carlsbad Cavern. But then the discovery and early exploration of Lechuguilla had confirmed it.

Evidence of rising, acid-rich springs clung to every chamber. This cave had clearly built itself from the bottom up, rather than the top down. The ancient chemical soup had deposited not only deep beds of gypsum but also sulfur, manganese, iron, and other ingredients to create bizarre mineral formations identified nowhere else on Earth. The exact chemical mechanisms by which the various strange formations had grown were the stuff of growing debate among geologists. Clues were just beginning to emerge from the world's active hot springs that biology might play a role in hot springs mineralogy, but few of those studying Lechuguilla considered this news particularly relevant to the study of cave formations. After all, the hot springs that had formed Lechuguilla had vanished long ago, leaving behind nothing but rocks and chemistry—so far as anyone knew.

The passage sloped into water so clear that we didn't know we'd reached it until the first person made a splash.

Eventually, we had reached the small pool called Last Water. The name had been an accurate description until a few months earlier. Explorers had since found deeper lakes in each of the three main branches of the cave. All the standing water in Lech was perched well above the region's natural water table. Although we were bound for the cave's largest known lake, discovered two months before and seen so far by only six people, we stopped to eat and fill our canteens at Last Water.

The otherworldly Lake Castrovalva
© Dave Bunnell

Several hours later, the caver who had discovered Lake Castrovalva, as our destination was known, had led us to a small arch, which we confirmed opened to a tunnel that resembled three coffins laid end to end. The far end of the rectangular passage sloped into water so clear that we didn't know we'd reached it until the first person made a splash. We could see that a few feet ahead, a ten-inch airspace opened to blackness.

Tucked into a rock shelf above the waterline were two one-man inflatable rafts. They had been hauled in—with great difficulty—by the original mapping team, after their discovery trip had revealed the extent of the water beyond. We decided to wait until "morning" to cross beneath the arch into a series of three small, wet rooms that would lead us to Castrovalva proper. We returned to the dry antechamber and made camp.

On the waterfront

I awoke to footsteps.

A carbide lamp bobbed up the slope and away, heading toward the closest flagged rock, located several chambers back. Across the room the team's photographer and leader fired a portable backpacking stove that whines like a jet engine. He bled the flame and set about boiling water for our breakfasts.

"Up and at 'em," he said, much too cheerfully.

One by one we took turns visiting the "designated rock." Warmed by instant oatmeal, we began packing gear for a full day of photography. Our target lake lay just beyond the small tunnel at the bottom of our slanted room. Gradually, we drifted toward this low exit, dragging our packs by their shoulder straps. We wrapped nylon duffels of photo gear inside doubled garbage bags, sealed them, and wedged the green bundles onto the rafts. Then we did the same for our own gear, our boots, and then finally our clothing.

white stalactites — Stalactites of selenite, a transparent, crystalline form of gypsum
© WGBH Educational Foundation

Except for helmets and attached lamps, we would enter the water exactly as we had entered the world. The rafts would keep our clothes dry as we swam them to the other side. But we were skinny-dipping for a higher purpose: to keep the water clean. The dirt on our clothes and boots would have muddied the lake; the dirt on our bodies, we presumed, would at worst merely cloud it.

Water from Lechuguilla's deeper pools, and the water in this pool was the deepest yet found, had tested as absolutely pure, purer than the testing laboratory's "pure" standard. Of course, the laboratory had tested the water only for pollutants and known organisms, but it really looked clean. It contained no filterable agents that could be cultured on standard growth media. Nor did it contain the trace radiation common to groundwater in New Mexico. This meant it had reached this reservoir sometime before July 16, 1945, the day the Manhattan Project left tiny, measurable bits of Trinity in all the surface waters of the American Southwest.

Lake beneath the desert

Because we had two boats, we elected to cross in teams of two, swimming the gear across the 100-foot-long lake, which had an estimated depth of 50 feet. Stoop-walking past me in the coffin-shaped room, the photo assistant grabbed the towline and splashed forward. The two of us began to guide the first boat toward the arch while the photographer continued packing lenses and film in the second. We immersed ourselves in the cool 67° Fahrenheit water.

I whooped and hollered at the chill.

She had to duck to fit her helmet through the arch before turning to pull the raft. It completely filled the hole, stuck fast.

myriad stalactites on ceiling — In places you have to watch your head for all the stalactites.
© WGBH Educational Foundation

I pressed down on the inflated sides, wriggling and shoving until it noisily slid through. I ducked and followed. We repeated the process through two larger hallways in the watery tunnel beyond, before the ceiling vanished far overhead. We were suddenly swimming in deep water, bound on all sides by immense bulbous calcite formations similar to those I had seen in Lake Lebarge, but larger and more profuse. Some crowded the walls; others seemed to float on the surface, as though their sides had lightly docked against the walls moments before.

Here I was, in a vast lake beneath the desert, the eighth human creature in this place.

Cave geologists had named these rose-colored mounds "mammillaries," for obvious reasons. I noticed that some of those projecting into the water were topped by dark, rigid mineral nipples. The mammillaries had grown by slow accumulation of calcite on all surfaces then underwater. Now ripened like massive fruit, each must have weighed tons.

I pushed the boat into deeper water. The photo assistant pulled, swimming backward. Overhead, wet stalactites dripped and glistened.

I hollered again, not from cold but to hear my voice bounce back from the black distance. Here I was, in a vast lake beneath the desert, the eighth human creature in this place, following the seventh as she pulled an inflated shell across one of the most beautiful chambers I had seen in a decade of caving.

Moist mammillaries on the shore gave way to massive broken pillars and columns beyond. The ceiling's canted arches and vaults seemed exquisitely planned, like the broken ruins in Botticelli's "Adoration of the Magi." Layers of sweat and grime rose from my flesh like original sin, and I was seized by an overwhelming urge.

blue water thru orange rimstone — Window into another world: A natural hole in shelfstone offers a glimpse of a clear pool below.
© WGBH Educational Foundation

Delving deeper

Treading water, I removed my helmet and wedged it between gear bundles on the raft so that it pointed back at me. I pulled off my glasses and fixed the neoprene sports strap to the boat's nylon line. Then I held my breath and plunged. Shadowy rocks poked from below. I swam down, down, as though following a plumb bob's quiver toward the vibrating heart of the world. The lake's coldness on my open eyes felt strange; my vision turned suddenly tactile.

At last I rolled, and water rushed into my ear. Above I could see the bottom of the boat, our two small lights flickering over the disturbed surface, the photo assistant's legs scissoring as she guided the raft toward a small outcrop in the center of the lake. My heart pounded in my chest. The water felt purer than anything I had known. I blew out a few bubbles. Then I deliberately swallowed a great gulp of the stuff. No taste, just a quenching coolness. This is, I thought, as far from life at the surface as it gets.

Fully baptized in Lake Castrovalva, I kicked back toward the light.

"Tastes great," I said as I surfaced. "And less filling."

We tied the rafts on the island and rested for a few minutes. The second boat soon popped through the arch. The photographer requested that we unpack a flashgun, a converted flashlight that fired old-fashioned blue bulbs. He took a few quick shots from his raft, shouting "Fire!" as we bathed the room in brilliance. Then we repacked the gun and spent bulbs and swam on. The four of us climbed onto the stone shore of the formation-draped chamber beyond the lake. We unloaded the rafts, dressed, and spent hours photographing geologic wonders. I stood in awe at some of the most beautifully decorated cave I had ever seen. Massive stalactites in pink and orange pastels flowed into mounds of white rippled flowstone. Calcite cave pearls sparkled amid multilevel rimstone pools.

cavers at Lake Lebarge — Cavers descend to the edge of Lake Lebarge, one of the most beautiful pools in Lechuguilla.
© WGBH Educational Foundation

Teeming with life

Much later, as we began the long journey back to daylight, heading out from what remains one of the most enjoyable caving trips I can recall, I once again drank deeply of Castrovalva. I never imagined that with every drop, I was swallowing life.

A decade later, after a half dozen additional expeditions to Lech, I would slowly come to realize that it was all alive. All of it: the water itself, the mammillaries, the gypsum bushes and crystals, the rock flour, the stalactites. Every surface I could see and many more that I couldn't thrived with unknown, invisible ecosystems, far more diverse in their species and their many strategies for survival than the population of any tropical rainforest. These creatures had played a role in shaping the strange beauty of the cave, just as their ancestors had governed the courses of the ancient sulfur springs that had carved its passages.

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