Late one night years ago in New York, I followed a friend off the edge of a subway platform and into the dark. In the most remote stretch of the tunnel, he ducked into a hidden alcove, where he pulled a metal panel from the wall. I found myself peering into a dark passageway, falling away at our feet. We descended, the sounds of the city receding, until we emerged into a giant void. It was an abandoned subway station, built a hundred years ago but never used, now unknown to the city. A ghost station, my friend called it. It was the feeling of touching down on a distant planet. But as we passed our light beams through the dark, it was not desolation that I saw—the chamber was teeming with signs of activity. Artwork tumbling over the walls, squatter campgrounds scattered across the floor, countless relics from a century’s worst of visitors. As we climbed back to the surface, returning the metal panel over the passageway, then clambering up to street-level, I was reminded that a whole separate realm exists beneath the surface, a world full of unexpected life and light.
We know astonishingly little of what lies beneath our feet. Up here in the sunlit surface world, we’ve explored and mapped every inch of land. Satellite imaging affords us a kind of Olympian view, where we can zoom in on distant rainforests and mountain ranges and desert oases. But the underground is obscure. It is no accident that the ancient Greek word for the underworld, Hades, translates to “the unseen one,” or that scientists refer to the deep parts of caves as “the dark zone.” Hidden beneath your feet at this very moment, there are webs of secret tunnels and clandestine government bunkers. Buried prehistoric cities and unknown tombs containing the bones of ancient chieftains. Hidden root systems carrying secret messages between trees and deep caves adorned with artworks unseen for thousands of years. In my years of exploring and documenting underground spaces, I have come to see the planet’s subterranean lands collectively as a lost continent, sprawling everywhere underfoot, always out of view.
“The deepest we’ve burrowed underground is the Kola borehole in the Russian Arctic, which reaches 7.6 miles deep—less than one half of one percent of the way to the center of the earth.”
We are a species of surface chauvinists. We forget about the underground—out of sight, out of mind. Our most celebrated explorers venture up and out—sailing out to unseen horizons, skipping across the moon—almost never down and in. No landscape on the planet is so close to us and yet so inaccessible. A journey from where we now sit to the center of the earth is equal to a trip from New York to Paris, and yet the planet’s core is a black box. The deepest we’ve burrowed underground is the Kola borehole in the Russian Arctic, which reaches 7.6 miles deep—less than one half of one percent of the way to the center of the earth. Geologists believe that more than half the world’s caves are undiscovered, lying deep in impenetrable crust.
We have been conditioned to abhor the underground, to turn away from the depths. Storytellers have long used the subterranean landscape as a way to fill us with terror. Think of Buffalo Bill stalking Clarisse Starling through the dark basement in Silence of the Lambs, of Pennywise the clown snatching kids into the sewers in It. Even the news stories about the underground that enter popular consciousness—the Vietnamese boys stranded in the cave in 2018, the Chilean miners trapped inside the earth in 2010, the Austrian girl shackled by her father in the basement in 2008—read like horror tales. Our bias against the underground is embedded in our language: we want to feel “uplifted,” to seek “highs,” never to feel “low” or “depressed.” Ultimately, our fear of the dark, our claustrophobia, our aversions to the underground are innate, rooted in biology. We are a species evolved for life on the savannah, adapted to subsist on abundant sunlight and oxygen, open horizons and long sightlines. Dropping into a dark cave is like entering the upside-down.
“But it is also a womb, a place of genesis: traditional cultures all over the world, especially Native American tribes, tell stories of ancestors germinating deep within the earth and slowly emerging on the surface.”
But the truth is, we are deeply connected to the underground, and always have been. Humans have been exploring and telling stories and dreaming about subterranean space for as long as our species has existed. Virtually every accessible cave on the planet contains traces of people from the past. For our ancestors, the underground was a crucial part of making sense of reality. In their eyes, caves were spiritual portals. When they crossed the threshold of a cave, and entered an environment of darkness and booming echoes and bewildering stone formations, they believed they were leaving normal surface reality and entering an otherworld. Everywhere we find accounts of seers, prophets and heroes going into the dark zone in search of illumination. Elijah first speaks to God in the depths of a cave. Muhammad communicates with Allah in a cave in Saudi Arabia. Native American shamans conducted vision quests in caves. Aeneas descends through a cave into Hades to consult the spirit of his father. When archaeologists explore caves today, they find remnants of religious rites: sacred paintings, burials, precious stones, sometimes even entire temples constructed in the dark. These subterranean ceremonies may well be humanity’s most universal, oldest, perhaps our original religious tradition. Not long ago, at the bottom of a cave in northern Spain known as Sima de los Huesos, archaeologists discovered evidence of a religious ritual performed six hundred thousand years ago, which is currently considered the very first evidence of religious behavior.
Over millennia, the subterranean landscape, like a prism, has come to reflect so many different aspects of our existence. We know the underground as the land of the dead, our burial place, our final destination. But it is also a womb, a place of genesis: traditional cultures all over the world, especially Native American tribes, tell stories of ancestors germinating deep within the earth and slowly emerging on the surface. Of course, the underground represents things forbidden and threatening, but it has always been a refuge, the place we burrow to shield ourselves from danger. We dig down in search of treasure and riches—gold at the bottoms of mines, oil in the fracking fields of Pennsylvania—but we also dig to bury our hazardous waste, much as we entomb nuclear remnants in the deep tunnels of Onkalo in Finland. Psychologists associate the underground with repressed memory, with things forgotten and unspoken; at the same time, the world’s caves have always been a place of revelation. “The underground metaphor,” writes scholar David L. Pike in his book Metropolis on the Styx, “can be expanded to encompass all of life on earth.”
“It is as though the underground is calling for our attention, reminding us that we must continue to look down, to peer into the dark for a deeper understanding of our world.”
Gone are the days of cave rituals, at least in the modern west. But our connection to the underground has never been more urgent. On a planet that is growing steadily warmer, where heat waves are intensifying and ice fields are receding, the underground is like the front line in a battlefield. The long-hidden aspects of our planet are coming to the surface in disturbing ways. In Norway, ancient artifacts long-hidden in the ice—a wooden ski, a leather sandal, Viking swords—are rising to the surface. Following a rampant heatwave in the United Kingdom, the shadows of prehistoric structures emerged in the earth. Most disturbingly, as the permafrost soils of Siberia begin to thaw, deadly viruses are rising out of the earth like ghosts. In 2016, a child died in an outbreak of anthrax said to emanate from once-buried reindeer carcasses newly exhumed by the melting earth. It is as though the underground is calling for our attention, reminding us that we must continue to look down, to peer into the dark for a deeper understanding of our world.
I have not returned to that secret hollow beneath the streets of New York. But it is never far from my thoughts. From time to time, on walks through the city, I will pause on the sidewalk directly above that space, and let my thoughts earthworm down through the pavement into the city’s invisible layers. It is a simple act, but by holding this landscape in my head, by meditating on the spaces unseen beneath me, I am reminded of how much larger and deeper and more mysterious the world is than we realize.