Mammoth Cave National Park

Local Indians knew about Mammoth Cave long ago. It was about 2000 B.C. when, no doubt impelled by normal human curiosity, they first ventured through the entrance, a gaping hole on a forested hillside, overlooking the Green River far below.

To find their way as they penetrated this dark and silent underground world, the Indians fashioned crude torches from bundles of giant cane, a tall, tough relative of bamboo that still grows in dense stands beside the river. (Scorched remnants of their torches have been found in many passageways inside the cave.) Probing the unknown depths must have been an awesome experience for these first adventurous explorers. In the hushed interior of the cave, their normally muted footsteps must have echoed distinctly, even ominously. In the flickering torchlight, their own shadows probably danced like giant ghosts across the cavern walls.

Advancing even deeper into the labyrinth, the Indians found many wonders to reward their curiosity: rivers that flowed underground; massive rock piles where cave ceilings had collapsed; stone formations that looked like icicles, columns, and billowing windblown drapery. Most wonderful of all were scattered chambers lined with deposits of gypsum crystals, some of them glittering and white like snow, gypsum in fluffy cottonlike masses, in fragile needles that shattered at the slightest touch, even in the shape of startlingly realistic flowers that sprouted from the walls. These were the prizes that kept the Indians returning to the cave for centuries: they mined the gypsum, which they are believed to have used for ceremonial purposes. (It probably was a valued trade commodity as well.)

Signs of the Indians' comings and goings are plentiful in the cave. In some places their footprints have survived in the soil, undisturbed by wind or weather for thousands of years; long-forgotten sandals and other articles of clothing, finely woven from local plant fibers, have been retrieved from the depths. But the most impressive discovery was made in 1935, when the mummified body of an Indian gypsum miner was found about two miles from the cave entrance. Killed about 420 B.C., he had been crushed by a five-ton boulder dislodged by his own digging. His body, his clothing, even the remnants of the last meal in his stomach, all were perfectly preserved. The body of "Lost John," as he was subbed, remains in the cave.

Then, for unknown reasons, the Indians abandoned Mammoth Cave about 1,000 years ago. It was not rediscovered until the 1790's when, according to legend, a hunter named Houchins stumbled upon the entrance while tracking a wounded bear. Whatever may have been the case, settlers soon found a new use for the cave. During the War of 1812 they began to mine its extensive deposits of nitrate, which was used to make saltpeter, a major ingredient of gunpowder. (Foreign supplies of both saltpeter and gunpowder had been cut off by the British blockade of shipping.) Visitors can still see the miners' leaching vats, wooden pipes, and other paraphernalia that remind us of Mammoth's brief but crucial role in the nation's history.

Modern exploration of the cave began in earnest in 1838 when a local lawyer bought the property for development as a tourist attraction. For the role of guide he chose his 17-year-old black slave, Stephen Bishop. The choice was an ideal one, for Bishop seems to have been afflicted immediately with a case of cave fever. Insatiable in his curiosity to know what lay around the next bend and beyond the next rockfall, he threw himself enthusiastically into the task of unraveling the cave's mysteries. By the time he died in 1857, he had discovered some 10 miles of major passageways and earned an unrivaled reputation as Mammoth's greatest explorer.

Yet even Bishop's work was only a beginning. Over the years, intrepid explorers added mile after mile to the known extent of the cave. Inching their way through cramped passages, enduring agony and fatigue, these mud-caked adventurers probed ever deeper into the labyrinth. And in time there came the realization that Mammoth Cave is mammoth indeed.

Its size keeps growing, not only because the forces that created it are still at work, but also because the underground world is by no means fully explored. In recent decades the focus has shifted from unraveling the mysteries of Mammoth's maze of corridors to finding links between Mammoth and the other cave systems that riddle the surrounding plateau. The enormous Flint Ridge system a little to the north of Mammoth was a particularly tantalizing target. For years explorers tried to find a connection between the two, but met with only dead ends and disappointment. The payoff for their efforts finally came in 1972 when, working south from Flint Ridge, a young woman, Patricia Crowther, wormed her small body through yet another muddy hole, which was later to be named the Tight Spot. A short distance beyond, and she had her companions soon spotted a metal handrail: they were in Mammoth Cave. The two systems in fact were one, a single cave with a total of 144 miles of interconnected tunnels and passageways.

More discoveries followed. In 1979, cavers found a link between Mammoth and Proctor Cave, to the southwest. Then in 1983, crawling, squeezing, climbing, wading neck-deep through water, they discovered a connection with Roppel Cave, beyond the boundaries of the park. That brought the total mapped length of the Mammoth Cave system to 294 miles, by far the longest cave in the world. (Its nearest rival, in the U.S.S.R., is only about one-third as long.) And no one knows what the future may reveal as cavers continue to probe the secrets of this realm of eternal darkness.