Dive Into the Depths of Carlsbad Caverns

At 750 feet underground, the Big Room sits at about the same level as the highway into the park, before it begins climbing up an escarpment to the parking lot. It’s one of North America’s largest, deepest, and most ornate caves. To reach it, we take an elevator down the equivalent of 75 stories—a ride that lasts a full minute—then walk through the edge of the Big Room, under a jagged ceiling, and through a gate, then switchback downhill past a landslide. In the jumble, a smooth boulder blackened with lantern smoke carries the etched names of early guano miners, who had likely ventured far from their work to see these chambers.

“Everyone okay if we play around with some cave darkness?” Boime asks before turning off all the electric lights, save his flashlight and two lanterns held by members of our group.

He walks us into the King’s Chamber with just lantern light illuminating the features as dim, pale forms in an indiscernible distance and against a darkness that seems endless. We sit at twinned rows of benches, facing the emptiness, as he tells the stories of the first recorded explorers of these caves, who saw them under similarly unfavorable conditions—and had no hope of ever finding a way out again if they dropped the lantern or torch and lost the flame. Then he flips on the lights to reveal the chamber, a massive gallery of draped stone curtains, fingers, and columns—every surface roughened, tasseled, or embellished with more stones so bent and curved they look as if they might move.

Centuries ago, Indigenous people revered the caverns, their presence evidenced in ancient firepits around the Guadalupe Mountains and pictographs at the caves’ edges. Jim White, a 16-year-old cowhand from Texas, documented his probing of the caverns just before the turn of the 20th century. He’d spotted a dark cloud of what he thought was smoke and followed it to find thousands of bats emerging from the natural entrance, the maw-like opening that hints at adventures below.

He descended into the caverns in 1898 with a “Mexican friend,” whose name is now lost to history, on ladders made of wire and fence posts. One of them still dangles from the Big Room into a 90-foot hole that leads to the Lower Cave. White became a champion of the caverns and one of their first known explorers, going on to map more than half of the recorded passages in the park’s main attraction, Carlsbad Cavern.

We pass under one of his survey markers—a neatly etched number 32—in the stone along a natural passageway into the Queen’s Chamber. Boime flips off the lights for real and leaves us in the dark and quiet.

In 1915, White led photographer Ray V. Davis into the dark. Davis’s black-and-white images of pale pillars against the gloom in what he had called a “fantastic fairyland” were printed in the New York Times in the early 1920s and spiked interest.

President Calvin Coolidge created Carlsbad Cave National Monument on October 25, 1923. In his declaration, Coolidge acknowledged that little was known about what the chambers contained, or even what remained to be explored, but said that what was known gave reason to expect that the stalactites, stalagmites, and other formations would rival better-known caves in “number, size, beauty of form, and variety of figure.” Congress granted the caverns national park status in 1930. Carlsbad Cavern—the park’s namesake cavern—is more than 30 miles long. The 8.2-acre Big Room is the largest and most readily accessible cave chamber in North America, according to the National Park Service.

Read more: A new book assembles 30 years of exploring the still-mysterious Lechuguilla Cave.

The first modern people to spend extensive time in the caves were guano miners, who began extracting thousands of pounds of nitrogen-rich bat guano for fertilizer in 1903; White led the first visitors down into the caverns in guano buckets. The miners built a hoist over what’s called the cave draw entrance, chosen because the natural (and current) entrance hits a 65-foot drop people had no way to navigate at the time. Visitors today have their choice of hiking more than a mile, steeply downhill, to enter the caverns through the natural entrance, or taking the elevators—the first shafts for which were blasted in 1931—from the visitor center.

Why can’t we freely roam everywhere? In Carlsbad Cavern, heavy traffic has changed the ecosystem—hair, trash, and lint are left behind. Carbon dioxide that humans exhale fills the cave over the course of the day (but the cave “breathes,” exchanging what’s inside for new air from outside every day or so).

Smudges of oils from human skin have tarnished the speleothems, the mineral deposits that make up stalactites and stalagmites, next to the trail, hazing them gray and blocking their growth. Discarded skin cells have even begun providing crickets, new residents to the cave, with a feast. Plus, after allowing self-guided tours to other areas, like King’s Palace, park staff noted excessive damage in those places, including broken forms. It’s still possible to spot the flat ends of stalactites that have been broken off for souvenirs. Guided tours of King’s Palace, as well as adventure tours to other caves, took over in 1993.

What cavers find inspires awe. The features and shapes both defy expectation and remind us that nature builds in patterns, that the same shapes echo among life-forms and geologic ones.

The caverns are notable worldwide, according to UNESCO, which designated the area a World Heritage site in 1995 for the size, abundance, diversity, and beauty of the rock formations found there. And the caverns’ evolution is ongoing. Although things are moving more slowly now than they did in millennia past, the same forces of trickling, mineral-rich water that built these forms continue to add to some of them year after year, offering a rare view into how the features develop.

Forms take different shapes, depending on the behavior of the water that helps create them. Slow dripping water leads to stalactites, which hang from the ceiling. Faster drips pile calcite up on the floor, where it becomes stalagmites, spires that seem to emerge from the ground. The two can meet in columns.

Where water curls down sloped cavern roofs, it drapes into “flowstone.” Soda straws develop where water seeps through a pore in the stone, its mineral content forming the tube through which it runs until it clogs and converts to a stalactite. The longest flowstone in Carlsbad Caverns extends about seven feet and is so fragile that a poorly steered bat wing could break it off.

But, Boime says, “speleology”—the study of caves—“is a new frontier, and there’s lots of debate.”

He points to a tangle of noodle-like formations called “helictites” hanging overhead, the only cave structures that don’t form in a line that follows gravity. No one is sure how they pull that off. But in a cave, it’s tough to be sure of anything. Our perceptions of distance, size, and color skew. The Green Pool, which we pass on the way out, certainly looks to have borrowed hues from the Emerald City, but that’s just a trick of the light. We cannot really know what we’re seeing—and we can’t truly imagine what anyone has yet to see.

Read more: Pack a strong flashlight (just be mindful of other visitors’ eyes when aiming it) and take a closer look at some of the Big Room’s features.