There’s a lost continent waiting to be explored, and it’s right below our feet. We’ll dig into the deep human relationship to the underground—and why we understand it from an instinctive point of view, but not so much from a physical one. (Hint: We’re afraid of the dark.) National Geographic photographer Tamara Merino will take us subterranean in Utah, Australia, and Spain, where modern-day cave dwellers teach us how to escape the heat.
HARRY KYRIAKODIS (HISTORIAN): They had wanted to move out of the caves into more permanent English-built structures. The caves were only a temporary place where the first settlers arrived in.
DAVAR ARDALAN (HOST): It’s the year 1681. Followers of William Penn have arrived in the new world from England, looking for religious freedom. Once here, on the banks of the Delaware River, they create homes out of the earth itself. In caves.
KYRIAKODIS: The settlers, their inclination was to build on the waterfront. And that’s what they did.
ARDALAN: Historian Harry Kyriakodis describes those early days.
KYRIAKODIS: The future Americans settled in these holes, which had been already there by the river for the possible catching of muskrats by the Indians.
ARDALAN: This small community, started in those caves, will very shortly become the city of Philadelphia, the first capital of the United States. The Quakers eventually moved out, but the caves continued to be used for many decades as the city grew. They became bars and brothels.
KYRIAKODIS: While others became part of the basements of houses along Front Street. And those houses or those businesses still exist along one certain area of Front Street. That’s part of Old City Philadelphia.
ARDALAN: And the caves are still there, deep under the homes of the busiest parts of Philadelphia, very close to where Highway 95 intersects with the Benjamin Franklin Bridge. Kyriakodis has been in one.
KYRIAKODIS: It looked like a basement. But, you know, from descending into it that you're going deeper into Earth than the outside area that you came from.
ARDALAN: Going deeper into the Earth—that instinct has played a part in human history in ways that we can’t always see. But it is part of our collective history, our present, and perhaps our future.
Where you may be standing at any given time is only part of the story. There is much, much more down below.
I’m Davar Ardalan, and this is Overheard at National Geographic, a show where we eavesdrop on the wild conversations we have here at Nat Geo and follow them to the edges of our big, weird, beautiful world.
And today we’re going underground. We’ll get to know the modern-day versions of underland dwellers in Hatch Rock, Utah; Coober Pedy, Australia; and Sacromonte, Spain— communities who choose to live in caves, away from daylight, in the depths of the earth.
More after the break.
WILLIAM HUNT (AUTHOR): I think of the underground as like a lost continent. There’s so much down there that we do not understand, that we cannot see, that it's just like this weird frontier for exploration. Weird in that it’s really close to where we’re sitting right now, and yet it’s completely alien.
ARDALAN: William Hunt has been exploring the lost continent of the underground since he was a teenager. He’s a cave expert and author, who thinks about what is below our feet constantly.
HUNT: As far as what is directly beneath us right now, anywhere you go in the world there are these nests of infrastructure that we never think about. There are ancient buried cities, archaeological sites. There are caves that may be totally unexplored. There are, beneath that, giant tectonic plates that are grinding up against each other. And then way down beneath that is the core of the Earth, which is basically like a black box as far as we’re concerned at this point.
ARDALAN: We’ve barely made a dent in our understanding of the caves and tunnels that make up our Earth’s underground. Hunt says by some estimates, half of the world’s caves are unexplored. And yet our fascination runs deep.
HUNT: Caves are sort of like the hidden aspect of existence.
ARDALAN: It’s the hidden aspect of existence that Chilean photographer and National Geographic Explorer Tamara Merino set out to find underground. The images she brought to the surface show us how whole communities live their lives in a seemingly unconventional fashion.
They venture into the darkness every day for very different reasons. Reasons which nonetheless connect them to our prehistoric—and even prehuman—relationship with caves.
TAMARA MERINO (PHOTOGRAPHER): The first time I went to the darkroom and I saw how my images started appearing, you know, these grains. They start like appearing, this photograph. I thought this was a magical moment, and I wanted to do this for the rest of my life.
ARDALAN: Tamara Merino uses photography to share hidden stories, including her powerful images of life underground. Her work has taken her to the Utah desert, the Australian outback, and Andalusia, Spain—all in the name of helping us imagine what we cannot see.
[Sounds of music]
In Paris in the 1860s, it was a photographer who captured the city’s imagination of the now infamous subterranean Parisian world.
HUNT: So Félix Nadar, who just went by Nadar, was a sort of fixture in the sort of bohemian art world of Paris in the 19th century. He was extremely flamboyant. And in 1861 he invented a battery-operated light, which is the first of its kind in photography. It allowed a photographer to take pictures without natural light. And to show off his magic lantern, as he called it, he took it into the darkest place you could find, which is the catacombs and sewers of Paris, and spent several months taking photographs of the hidden underside of the city.
ARDALAN: Nadar and his crew lugged heavy equipment down below. Each exposure took 18 minutes.
HUNT: When the photographs were published, they had this really profound impact on the imagination of Parisians. People who knew that their city had these underground systems beneath it. They knew about the catacombs; they knew that the sewers were down there. They were mostly kind of dark, threatening, unknown spaces.
ARDALAN: Nadar’s photographs illuminated a part of the city that Parisians couldn’t see.
HUNT: They saw these images and they became fascinated and they wanted to go visit these places. People would, you know, dress up in their Sunday’s finest and go wandering through these dark tunnels. It became sort of a fad, on a weekend night, to pop open a manhole and climb down into the sewer system and sort of walk in the footsteps of Nadar. And he’s described as this sort of mythological hero who has traveled to the land of the dead and reemerged on the surface with a new kind of power.
ARDALAN: That power of going down into a cave, into the belly of the Earth, and coming back to tell the tale is the most powerful story of the underground. And it goes all the way back to the beginning of human history.
HUNT: If you look at the mythological systems of cultures all over the world, it’s universal. There’s always an underworld, even with cultures that don’t have physical caves around them. There is an underworld.
ARDALAN: Ancient cave dwellings can be found all over the world. In places like Matmata, Tunisia; Kandovan, Iran; and inside the high cliffs of Mesa Verde, in what is now the southwestern corner of Colorado.
And today some 30 million people currently live in caves in China, burrowing inside the yellow, porous soil of the Shaanxi Province. President Xi Jinping reportedly lived in one of these caves for seven years as a young man. His parents were exiled there during the Cultural Revolution.
A red dirt road is the only approach to Hatch Rock. In Tamara’s aerial photo, the road splits into a V, framing a huge red rock that rises nearly 500 feet out of the landscape.
MERINO: I arrived to this massive rock in the middle of the desert, and this was like a—it has the crescent shape of the moon. And it was amazing.
ARDALAN: Tucked into the base of Hatch Rock is Rockland Ranch, a community of modern cave dwellers in eastern Utah.
MERINO: These caves are built in the massive red sandstone formation. So the houses were built by blasting dynamite into the sandstone cliff and then covering the cave walls to create modern homes with running water, electricity, internet access.
ARDALAN: The community who has lived here since the 1970s are fundamentalist Mormons. They refer to this place simply as “The Rock.” Enoch Foster is the son of the Rock’s original founder. Self-sufficiency is a basic tenet of this polygamous community.
ENOCH FOSTER (HATCH ROCK RESIDENT): And so, over the last 15, 17 years, we’ve built 15 homes and cabins and solar systems and putting wells and putting water systems and water lines and garden lines and ...
ARDALAN: They live off the grid with their own water well and are powered by solar energy. This helps them stay under the radar in a state that outlaws bigamy, and to avoid the Mormon mainstream who shuns it.
FOSTER: Basically we want to live as naturally as we can, and living in the Rock helps us be able to do that, reduces our pollution, reduces what we need to sustain life.
ARDALAN: The images that Tamara captured at the Rock reflect a driving reason people have sought shelter in caves for centuries: to escape the apocalypse. Enoch Foster is carrying out his father’s vision, which was to prepare for—and survive—what they believe will be the end of days.
FOSTER: He believed in a time when the Earth was going to change to, to a different way of being, and he always believed that there would be wars and troubles come before that. So to come and begin building a community that he hoped would last into the far future.
[Sounds of music]
ARDALAN: There is a biblical passage that states, “And they shall go into the holes of the rocks, and into the caves of the earth.” The Rock is a very literal interpretation of that mandate.
When Tamara arrived, one family was in the midst of carrying it out.
MERINO: So that first day I helped them build the cave they were building. And it was really fascinating to see them, how they were turning this cave into a home. It was amazing. And there were still no lightbulbs on the roof. So the lighting was coming from the flashlights, from their hands, or from their heads. And it was really like, watching all these people working collectively felt like being inside an anthill.
ARDALAN: This act of creating space underground has compelled whole cultures to seek shelter in this fashion.
HUNT: I think that as dark and threatening as a cave can be, or as a subterranean burrow can be, as afraid as we are of being buried alive, there’s something deeper than that: that finds comfort in and being sort of embraced by by the earth, by feeling yourself in this kind of musty darkness and and recognizing In some glimmer of deep psyche, that you’re back in your mother’s womb.
ARDALAN: More after the break.
Across the globe, in the southern Australian outback, modern cave dwellers have been burrowing underground for an entirely different reason: mining.
Tamara found herself there in 2015—seemingly in the middle of nowhere—with a flat tire.
MERINO: I started looking at the landscape, and I was really enchanted because it has like a mysterious lunar landscape. The sand is really red, and it’s a deep orange. It’s beautiful.
[Sounds of chanting]
ARDALAN: For about a century, this extremely remote town has been known as the “opal capital of the world,” but Tamara says you wouldn’t know it from the surface. Everything from dive bars to restaurants to churches is built below the surface. And for good reason.
MERINO: So this was in November. So it was almost summer; it was really, really hot. It was almost 120 degrees outside.
ARDALAN: The extreme heat has driven the population to live alongside their precious opal, down below. But don’t call them caves. Locals refer to their homes as dugouts.
Tamara got her flat tire fixed, but she decided to stay and get to know some of the residents, including opal miner Martin Fageter. He invited Tamara to see the dugout that he calls home.
[Fageter’s voice speaking]
MERINO: When he opened the door, he gave me a head torch to walk through the tunnels of his underground house. And that was an amazing moment, you know? I remember thinking, If I need a head torch to walk around his town—I mean, I’m going to be walking in dark tunnels, you know?
ARDALAN: The dugouts in Coober Pedy hold steady at around 75 degrees Fahrenheit. Tamara captured the sense of coolness inside Gabrielle Gouellain’s home in a photograph of her kitchen—a room with raw cave walls. A piece of muslin is seen covering a hole in the ceiling. Tamara stayed here with Gabby for a few nights.
MERINO: And every morning when I woke up, my blanket was covered with dust and small pieces of soil that had fallen from the ceiling during the night. And I remember feeling that the earth was alive, you know? It was constantly changing.
ARDALAN: Tamara got to see just how much that underground was changing when she was invited to visit one of the opal mines.
[Sounds of debris falling and a motor reverberating]
MERINO: We went down 15 meters sitting on an electric winch, and it was a hole about one meter wide. And for a moment, this 45-second journey down seems like an eternity. This was the first time I was going down so deep in the earth. And when I was going down, little stones fell off while I was going down the shaft. Down in the mine was completely dark. And when we were down, they have just some spotlights on the entrance, and walking around with a torch on your hand is like going in a labyrinth that doesn't lead you anywhere, you know?
ARDALAN: The farther down she went, the more deeply she felt connected with one of the most ancient human relationships to the Earth.
HUNT: One of the oldest ways we’ve interacted with the underground is to go into the earth to extract valuable minerals from beneath the surface. It has always been a spiritual act—more specifically, a spiritually anxious act—across the world and throughout history. You find stories of traditional cultures going underground to mine minerals and having to appease a sort of a mine spirit, like an earth spirit that protects the mine.
ARDALAN: The opal mines in Coober Pedy still embody some of that ancient anxiety.
MERINO: Opal is there somewhere. They just have to find it. The stone is going to change their lives. They stay and live in the mine because they are afraid of somebody else coming and stealing their opal.
ARDALAN: The opal fever, as they call it, overrides the dangers of mining, when there is always the risk of collapse or underground flooding. And the chances of discovering opal of value are unpredictable at best.
MARTIN FAGETER (OPAL MINER): If you can find it. It’s needle-in-a-haystack stuff. But we came across the most beautiful opal. I went with the light and around the corner and this thing in the wall just … was like a third eye, right? It was orange, and it was beautiful. And it was just glittering with sugared opal, bright orange. Nature creates anything you can imagine.
ARDALAN: Tamara says for Martin Fageter, the value of living underground goes well beyond the elusive opal. It’s a way of life.
The tradition of underground living in Australia has been prized for millennia by aboriginal cultures, stretching back as far as 46,000 years to the Juukan Gorge caves in the Pilbara region. These rock shelters were decimated in 2020 by Rio Tinto, a mining conglomerate in search of iron ore. They have been ordered to restore the site.
[Sounds of music]
The scorching temperatures in Utah and Australia are undeniably part of the reason these underground dwellings are so eminently practical.
So practical, in fact, that William Hunt believes a strong case can be made for a future where caves will provide a refuge from the ever increasing impact of climate change.
HUNT: I don’t think it’s a stretch to say that, you know, we could be looking at a version of the future of humanity as things heat up and get really hot. It would make sense for us to take shelter in naturally cool subterranean settings.
ARDALAN: Could this be the way of the future? From her travels around the world, Tamara Merino thinks so.
MERINO: Living underground is an eco-friendly and optimistic solution for the environment, and it is completely self-sustaining, as in the case of Utah and in Coober Pedy, Australia, and it reduces the impact on the terrain through a carbon footprint of practically zero. You know, that leaves the caves with a constant temperature, so they don’t need heating system or air-conditioning system. So all these communities I have documented really show us how we can go back to the basics, because I feel like today we are the ones who have to inhabit the world in a different ways, and they are really being an example for us.
ARDALAN: With so much of the planet at risk from higher temperatures, it would seem that many might still need to be convinced of the benefits of dark, deep subterranean living. While underground life may not be for everyone, it’s already happening.
HUNT: It’s becoming more and more common to have apartment buildings that go not only above the surface, but deep below the surface. They’re already starting to build down into the ground to create large-scale housing for the population in East Asian megacities.
ARDALAN: If this is the case, then what does the future look like? How will our long relationship with caves impact the way we live our lives as the planet changes?
HUNT: I think of future archaeologists coming to look at our society now and in the immediate future. I wouldn't be shocked if they see this trend of retreating into naturally cool cave spaces or subterranean spaces in cities.
ARDALAN: If the caves in the Andalusia region of Spain are any indication, underground living is in no way on the wane. As one of the oldest, continuous cave-dwelling communities in Europe, it is thriving. According to Tamara Merino it is also enchanting.
Her photographs and videos of underground flamenco dancers show how much life is inside these caves.
MERINO: There were pans and pots hanging all over the ceiling.
ARDALAN: That ceiling was dome-shaped, painted white.
MERINO: The light was dim but not dark completely.
ARDALAN: A few colored lights glowed on the walls, in reds, greens, and blues. It’s moody and festive. Then a dancer enters.
MERINO: And she appears in the middle of the darkness and begins to dance. And on her face. I could really see an expression of nostalgia, like she was suffering, but I could tell that it was pure passion running through her veins.
[A voice singing]
ARDALAN: The room is captivated, but the crowd is small. On either side of the dancer, just a single row of chairs looks on.
MERINO: And she keeps on tapping. And suddenly she start rubbing her hands against her body until she reaches the ceiling. And then she started to clap really, really hard. You could feel, really, the vibration of the music in your skin. You could feel how it moves you. That moment, I started crying. Tears were falling down my face. But those were tears of joy, of happiness, because I felt like I was transported like 500 years back to see the first dancing of flamenco.
ARDALAN: This cave, near Granada, is part of Sacromonte, a mountain where caves have existed for hundreds of years. The residents have lived on the margins of larger society since it was founded. It’s where some Jewish and Muslim populations escaped to avoid being forced to convert to Christianity in 1492. And since that time, it has been home to thousands who are fleeing both the constraints of conventional life, as well as political turmoil.
This theme is strong in cave dwelling communities—as with the Mormons of Hatch Rock, or the Quakers on the banks of the Delaware.
Here in Sacromonte, on the outskirts of society, the zambra flamenco specific to this region was born hundreds of years ago. Similar to the caves, it was an act of resistance.
MERINO: And until these days, these gypsy families retain their traditional cave lifestyle, a life with more strength than ever.
ARDALAN: Today this mountain is porous with caves that are inhabited by people from all over the world, including immigrants from elsewhere in Europe and Africa. They are here, in part, for the freedom that comes with living underground. This is another powerful piece of the story of our relationship with caves.
HUNT: So that is something that I have seen a lot all over the world, where you have marginalized people who don’t have a place or don’t feel comfortable in kind of normalized surface spaces in a given place. And so they retreat into cave spaces.
ARDALAN: Tamara spent some time with a cave dweller named Tocuato Lopez, who was born in Sacromonte. The photo she captured is of a well-dressed gentleman, sitting in a room with a very low ceiling, surrounded by large, colorful stuffed animals.
MERINO: His room is in the deepest part of the cave. And this room does not have windows. It doesn’t have natural light. And Tocuato was sitting on the edge of the bed, with the photograph of his father hanging next to him on the wall. And it was really a magical moment, but a little bit spooky, I have to say, because not fresh air was coming in and the darkness of the earth could be really felt.
ARDALAN: Many of the residents of Sacromonte, like so many throughout human history, have deep, spiritual connections to places like this, where the darkness acts not as a threat but as a refuge.
MERINO: I remember Tocuato once told me, “I’m very proud of being from the caves, and I will die inside a cave.”
ARDALAN: National Geographic Explorer Tamara Merino. She hopes to travel next to Tunisia, Mexico, and China as she continues to document the lives of underland dwellers, digging even deeper into our human relationship to the underground.
If you like what you hear and want to support more content like this, please rate and review us in your podcast app AND consider a National Geographic subscription. That’s the best way to support Overheard. Go to natgeo.com/explore to subscribe.
The underland photos that Explorer Tamara Merino captured can be seen online at nationalgeographic.com.
Will Hunt’s book, Underground: A Human History of the Worlds Beneath Our Feet, will take you much deeper into that topic.
Links to these resources can be found in the Overheard show notes in your podcast app.
Overheard at National Geographic is produced by Marcy Thompson, Ilana Strauss, Brian Gutierrez, and Jacob Pinter.
Our senior producer is Carla Wills.
Our senior editor is Eli Chen.
Our fact-checkers are Robin Palmer and Julie Beer.
Our copy editor is Amy Kolczak.
This episode was sound-designed and engineered by Ted Woods.
This podcast is a production of National Geographic Partners. The National Geographic Society, committed to illuminating and protecting the wonder of our world, funds the work of National Geographic Explorer Tamara Merino.
Whitney Johnson is the director of visuals and immersive experiences.
Susan Goldberg is National Geographic’s editorial director.
And I’m your host and executive producer of audio, Davar Ardalan. Thanks for listening.
In Vietnam photojournalist and National Geographic Explorer Martin Edström created 360 images of the world’s largest cave, Son Doong. It’s so big that a forest grows inside of it.
Ever zip-line to a remote island? Cartographers did, 30 miles west of San Francisco. What did they see when they mapped the hard-to-reach landform known as the Farallon Islands? Caves.
China is home to some of the most intricate cave systems on the planet. These explorers used a laser scanner to capture never before seen images of undocumented caves.
South Dakota is famous among cavers for its web of cave mazes. Take a look at what they’ve found under the Black Hills.