The Hollow Core: Mammoth Cave National Park

Mammoth Cave National Park houses the largest known cave system in the world.

It’s not what you’d expect to see just fifteen minutes off the interstate in the rural South, but some of the most interesting sights never are. This exit has all the usual trappings, gas stations and fast food, but what really caught my eye was the name of the town: Cave City, Kentucky. It’s reminiscent of Speedway, Indiana: you know exactly what you’re getting into. Whoever named these towns was nothing if not pragmatic.

Other businesses take advantage of the number of people passing through; on the way to the park are haunted villages, mini golf courses, and even a museum with life-size dinosaur replicas. The natural wonder just up the road must not be enough for some.

The entrance is unassuming, and without the sign marking the beginning of National Park land you’d think the road inside is like any other. Once you come across the building, though, you might start to realize that something is up. A large parking lot lies in front of a wooden lodge- the visitor center. A small pavilion out front details the schedules of the guided tours and points you inside.

The interior houses ticket lines, gift shops, and crowds of eager tourists, many pacing back and forth hurriedly across the building to make their tour times. It also includes a museum, which takes guests through the history of the cave, explaining millions of years’ worth of erosion, ecology, and exploration. The back doors lead to a concrete bridge which connects to a restaurant. On this same porch there are more small pavilions, these set up for the guided tours. Groups of visitors huddle around their all-knowing guides. One park ranger rolls a cart full of lanterns out of a storage closet.

A trail snakes down to the left and threads underneath the bridge, taking a sharp downhill towards the cave. Several groups stop on this road, their guides explaining the importance of staying on the marked paths and turning off camera flashes in the cave; the bats there are sensitive to light. The road peters out at the base of the hill, drawing attention to a stone staircase with a guide checking tickets in front. He gives a safety briefing to a family choosing to embark on the self-guided tour.

This staircase leads down what is known as the Historic Entrance, the main opening into the cave for hundreds of thousands of visitors every year. Lush foliage dots the upper sections of the concave, and the moisture gives way to a tiny waterfall that dampens the edges of the stairs. The cavernous opening almost beckons you inside, towards a set of double doors that mark where the cave officially begins.

The first thing you’ll notice when entering is the sudden drop in temperature. While the descent removes direct sunlight from the equation, the cavern itself takes care of the humidity, too. You might even feel a chill as you stare further in, the darkness taking hold even with the help of artificial lights along the walkway. A placard nearby explains the effects of the twilight zone, a threshold within which natural light may no longer be seen. Sunlight may not enter here; this journey is between you and the earth.

The cave narrows as it goes, but still allows you to stand up straight. Just as it seems you would have to begin watching your head, the roof opens to a spectacular sight. An underground chamber rises up and out like an amphitheater underground. This room is known as the Rotunda on account of its shape; within the ceiling, a nearly perfect circular pattern appears, emanating out from the center. Guardrails block off the middle of the chamber, where old mining equipment lies untouched. A ranger stands at the rail, quietly surveying the scene.

Perhaps the most striking thing about the cave, more so than the towering ceilings, is the dead silence throughout the chamber. On the surface, one may hear buzzing cicadas and chirping birds, or even in their absence, the wind blowing past their ears. None of that is present here; in the space between other visitors there is a piercing silence. You are fully immersed in a realm where sound is absent.

The cave openings extend in two directions, one of which may only be accessed on a guided tour. The second leads deeper into another set of towering rooms and hallways, all of them reaching at least two stories high. The tallest of these is about five, and sets the scale for just how deep underground you really are. Placards around this self-guided tour area explain the history of the cave, providing context to the dimly lit labyrinth you find yourself in.

Regardless of what you get out of the cave, one thing is certain: the cool, dark quietude is something you will not find in the world above.

Any noise in the cave comes from the other visitors, of which there are many. A group finds their way to the guided tour gate, led by a ranger who opens it. The visitors are each armed with a lantern, the same kind the ranger carted out earlier. One by one they descend into the depths in a straight line, their bobbing lanterns the only light piercing through the abyss. Their gentle chatter dissipates far more quickly than you would expect.

After one last look at the natural wonder, it’s time to return to the surface. It is bright and noisy, not unlike the feeling of stepping outside a movie theater after finishing a film. Although the cave is certainly the main draw, the park holds miles of trails, streams, and woodlands on the surface as well; over 52,000 acres, to be exact.

One trail leads uphill a short distance from the Historic Entrance to Dixon Cave, a much more unassuming hole in the ground. A placard here explains the sensitivity of the bats that sleep there, and some of the visitors reading it lament on how the animals being awoken can kill them. It’s in these moments where the significance of conservation and education around it shine through; for those unaware of the fragility of nature, just one spark in the right place can ignite a fire in someone’s passion for protecting what’s around them, or at the very least cause them to think differently upon receiving new information.

The aforementioned museum in the visitor center is packed full of tidbits like these, detailing the steady process of shifting sediment that created what the cave would eventually be. Outside of that, there are details about its history, from its prehistoric use to profiles of the explorers who would put Mammoth Cave on the map.

One that stood out to me was Frances Benjamin Johnston. Upon finding her way to the cave, Johnston, a photojournalist, was determined to document it. She would ignite a dangerous, volatile powder to produce flashes in the darkness, a technique which could injure or even kill her. However, she beat the odds to produce a series of award-winning photographs, the first woman to do so. The cave is filled with stories such as these, of daring adventurers risking their safety for thrills and recognition. The idea of descending into this cold darkness with only the equipment available in the 1800s is hard for anyone to imagine. It’s not quite accurate to say that these pioneers are obsolete today, but it’s certainly tempting to regard those from the days of old as being made of stronger stuff.

The visitor center is still packed, even on a weekday after most of the tours are over. Many chatter excitedly about what they had seen, and some head back to their cars. It’s an uneventful exit, the same healthy forests and rural roads leading back towards Cave City and then the interstate.

And yet, it’s hard to see things the same way once you leave, knowing of the hidden world that lies just below your feet.

All figures and additional research courtesy of the National Park Service.