From Cisterns to Temples, These Twelve Underground Worlds Are Open for Exploring

Although the lives of humankind play out on the surface of the Earth, for millennia people have explored what lies beneath. Some had a practical reason for venturing underground—quarrying stone for building material, digging out cisterns or mining salt. Others were drawn there for spiritual purposes, building shrines or transforming natural caves into temples of worship.

Whatever the motive, the drive to experience the subterranean world seems to be a universal one. The number of places around the globe where people have looked under the surface to find safety, religious ecstasy or solutions to early technological challenges is astonishing. Some historical underground spaces have even taken on new identities in the modern era, transforming into amusement parks, art galleries and restaurants in recent years.

From Romania’s Salina Turda to California’s Forestiere Underground Gardens, these 12 incredible underground worlds are open for exploration.

Actun Tunichil Muknal

San Ignacio, Belize

“In Classic Maya civilization, caves were considered portals to the underworld,” says Maya archaeologist Andrew Kindon. Actun Tunichil Muknal was uncovered in the thick, tropical jungle of Belize’s western Cayo District in 1989. Inside, researchers discovered a network of caverns rich with ritual artifacts over 1,000 years old: tools, weapons, ceramic vessels with ceremonial “kill” holes to release the spirits within them, and even cave formations modified into altars and otherworldly images. The remains of more than a dozen people have been found inside the cave, including the so-called Crystal Maiden, a sacrificial victim now believed to be a 17-year-old boy whose calcified bones sparkle in the light.

“Actun Tunichil Muknal is one of many caves in the region that likely served as sites of important spiritual pilgrimage,” says Kindon, and while it’s one of only a few open to the public, “there’s some concern over whether they should be allowed to enter such a sacred and fragile space.”

Those who do seek to visit won’t find Actun Tunichil Muknal, known locally as the ATM Cave, easy to reach. The only way to get to the three-mile-long cave is on a 45-minute hike through the Tapir Mountain Nature Reserve, followed by a swim to the entrance through a pool of water.

Basilica Cistern

Istanbul

Beneath Istanbul, the earth is honeycombed with cisterns, first carved in the sixth century to provide water for the rapidly growing Byzantine city. Now, close to 1,500 years later, archaeologists still do not know exactly where each one lies. The largest found to date, the Basilica Cistern, was built as the water source for the Great Palace of Constantinople in 527 C.E. Eventually, though, as new technology replaced older methods of water storage, the cistern was forgotten. The Ottomans rediscovered the chamber in the 15th century but, even today, the source of its water remains unknown. Renovated and opened to the public in 1987, the Basilica Cistern is now a subterranean palace of shadow and slowly shifting colored light, where haunting contemporary and ancient sculptures (including two massive Medusa heads) wade in the shallow pools. While none of Istanbul’s other cisterns draws the kind of crowds as the Basilica Cistern, a few have been preserved or repurposed into modern spaces, including the show-stopping fine dining restaurant The Sarnic.

Villa Torlonia

Rome

In 2011, an Italian government employee discovered a trapdoor inside a lavish, 200-year-old Roman palace, Villa Torlonia. Beneath it, a brick staircase descended 70 feet into a previously unknown underground bunker built to protect dictator Benito Mussolini, who lived at the estate with his family between 1929 and 1943. The secret chambers and passages—outfitted with anti-gas doors, an air purification system and four-foot-thick concrete walls—were opened to the public this spring. Although Mussolini was arrested before he could use the bunker, the immersive visitor experience includes a virtual re-enactment of how it would have felt to be hiding there during the World War II bombing of Rome by Allied forces.

Forestiere Underground Gardens

Fresno, California

“It was the Fresno summer heat that inspired Baldassare to move underground,” says Shera Franzman, director of operations for Forestiere Underground Gardens. Although the Sicilian immigrant Baldassare Forestiere had come to California’s Central Valley to establish a citrus orchard, he soon discovered his parched and sweltering land was full of inhospitable hardpan soil. So, in 1906, Forestiere, a onetime subway digger with a fourth-grade education, began to tunnel beneath it. By the time of his death in 1946, he’d created a subterranean agricultural oasis, an approximately ten-acre network of rooms, passageways and courtyards full of grape vines, berry bushes and groves of pomegranates, oranges and loquats.

“Baldassare designed his underground gardens with skylights that were strategically sized and placed to provide enough sunlight for his trees to grow, but not so much that he would lose the benefit of the cool underground home he had created for himself,” Franzman says. Forestiere dreamed of someday opening his grottos as a day resort for summer visitors. While he failed to get his wish in his lifetime, the gardens were opened to the public as a museum immediately after his death. Now a historic landmark, the underground gardens host guided tours seven days a week, and fruit from the innovator’s original groves is seasonally available at the on-site gift shop.

Elephanta Caves

Elephanta Island (Gharapuri), India

Although no one knows exactly when worshipers began carving the solid basalt cliffs of India’s Elephanta Island, archaeologists have found evidence of Buddhist occupation as early as the second century B.C.E. It wasn’t until at least the fifth century C.E., though, that the first of five rock-hewn Hindu temples was built to join two pre-existing Buddhist ones. The most elaborate and best preserved, a 128-foot-deep, human-made chamber, is dedicated to Shiva and filled with shrines, friezes and statues of the Hindu deity.

Unfortunately, most of the island’s other Hindu cave temples did not fare as well. While several still have some support columns, and the fragments of shrines and sculptures, it’s likely they were intentionally destroyed, possibly by the Portuguese, who converted one of two original Buddhist caves into a Christian church in the 16th or 17th century. Despite the damage, the Elephanta Caves remain a magnificent example of rock-cut architecture so universally valuable that, in 1987, UNESCO named them a World Heritage Site.

Batu Caves

Gombak, Malaysia

A little over a century ago, a limestone cave system north of Kuala Lumpur was reborn as a holy Hindu shrine. Once used for shelter by the Indigenous Temuan, then for mining bat guano, the Batu Caves got their first Hindu temple, the Sri Subramaniar Swamy Temple, in 1891. Dedicated to Murugan, the Hindu god of war, the temple has drawn Tamil pilgrims to celebrate Thaipusam, a Hindu festival held during the full moon of the Tamil month of Thai in January or February, there annually since 1892.

Over time, the multichambered site has welcomed a number of new shrines and statues. In 2006, a 140-foot-tall image of Murugan erected outside the cave became the tallest statue of the god in the world. Three other caves—the Art Gallery and Museum Caves, which tell the story of Murugan’s life, and the Ramayana Cave, which is painted in scenes from the Hindu epic Ramayana—are also open to visitors, and dancers perform hourly at the site. Guided tours are also available inside Dark Cave, a subterranean passage more than a mile long whose maw is located at step 204 of the 272-stair ascent to Murugan’s shrine.

Sacred Cenote at Chichen Itza

Yucatán, Mexico

The porous nature of the limestone karst that forms the foundation of Mexico’s Yucatán Peninsula has left the region riddled with caves and cenotes, or underground sinkholes filled with water. Like farther south in Belize, these were places of great spiritual significance to the ancient Maya. Among the most important was the Sacred Cenote at the city of Chichen Itza, says Kindon. “Archaeologists have found hundreds of offerings thrown into the water by priests and pilgrims, including jade, intricately carved plaques, and precious gold and copper objects rarely found at other sites,” he says. Human sacrifice also took place at the Sacred Cenote. A recent study confirmed that all of the victims, most of whom were between the ages of 3 and 6, were male, and many were twins or close familial relations. “In Maya mythology, the gods of the underworld are defeated by a pair of brothers called the Hero Twins,” says Kindon. “It’s likely the sacrifices at the Sacred Cenote were associated with that story.”

Visitors to Chichen Itza can see the Sacred Cenote from a hiking trail just above it, its waters green with algae, but swimming at this important archaeological site is prohibited. To take a dip, head to nearby Cenote Ik Kil, Cenote Yokdzonot or Cenote Kax Ek instead.

Derinkuyu Underground City

Nevsehir, Turkey

Up to 20,000 people once lived in the city of Derinkuyu in Turkey’s Cappadocia region. But Derinkuyu was not like other cities. Everything there, from its churches, schools and cemeteries to its barns, bedrooms and kitchens, was built entirely underground.

Construction at Derinkuyu may have begun as early as the eighth century B.C.E., but it wasn’t until the eighth century C.E. that the city was fully inhabited as a subterranean refuge from the Arab-Byzantine wars. Local people found not just relief from battle there, but consistently cool temperatures ideal for food storage. Since then, many others have found sanctuary at Derinkuyu too, including Christians in the 14th and early 20th centuries. Visitors today can explore about half of the 18-level city, which stretches almost 300 feet beneath the Earth’s surface.

Salina Turda

Transylvania, Romania

For over 2,000 years, humans have been extracting salt from beneath the earth at Turda, in Romania’s Transylvania region. With generation after generation chasing the precious mineral with pickaxes, hammers and chisels, the caverns grew into a full-scale salt mine containing multiple chambers up to 367 feet deep. Mining ended at Salina Turda in 1932, but its chambers weren’t forgotten. Salina Turda was used as a bomb shelter in World War II and, later, as a warehouse for cheese storage. In 1992, however, Salina Turda entered its most exciting phase yet, transforming into an otherworldly amusement park complete with a subterranean Ferris wheel, bowling alley, miniature golf course, a lake for paddle and rowboats, and a halotherapy spa. The remains of Salina Turda’s mining operations still remain, too, now eerily illuminated.

Napoli Sotterranea

Naples, Italy

Some 2,400 years of history exist within what Arianna Albertini, director of Napoli Sotterranea, calls the “womb” of Naples. At its deepest depths, close to 130 feet below the surface, Greeks quarried great caverns from the rock to build the city’s landmarks. Romans converted the quarries into a network of aqueducts to supply water to the growing city. Later, other features they built, including Roman theaters, were buried as Naples modernized its landscape. It’s all still there, deep under the city, and new discoveries continue to be made. Recently, says Albertini, “drain sewers from the Bourbon period made out of riggiole [tiles] with blue color designs” were revealed beneath the floor of the fragmented remains of a Roman theater. But not everything visitors can see in Napoli Sotterranea is ancient. Tours also wind through tunnels that were converted into air raid shelters in World War II, and the 115-foot-deep Hypogeum Gardens, “a vegetable garden growing in the bowels of the Earth,” says Albertini, that has been producing traditional plants since 2015.

The Paris Catacombs

Paris

The Paris Catacombs are an “empire of death,” according to the sign at their entrance. Beginning in 1785, more than six million individuals were buried there, in underground limestone quarries from which the stone of many of the city’s most famous monuments was extracted. A two-pronged solution for fighting the noxious scent of human decay and freeing up more land above ground for the living, the bones weren’t just stacked inside the Catacombs—they were used to build an entire labyrinth of macabre columns, arches and mosaics. One of the most famous subterranean sites in the world, the Catacombs first opened to the public in 1809. Since the 1950s, it has been illegal to go more than about a mile through the site’s 186 miles of tunnels, but Parisians have not always followed the rules. A special branch of the local police patrols the passageways in search of explorers and, occasionally, something more—like the hidden cinema and bar stocked with 1950s film noir classics and bottles of whiskey discovered in 2004.

Caves of Hercules

Tangier, Morocco

Millenia before ’80s rock gods Def Leppard turned up the volume inside the Caves of Hercules near Tangier, Morocco, it was a resting place for the superhumanly strong Greek and Roman hero Hercules—or so the legend goes. While archaeologists can’t verify that particular tale, they have some ideas about what came later. It was likely Phoenicians who broke through one of the cave’s walls, finding a sea-accessible shelter in which they left behind drawings of eyes in the shape of a map. Later, while quarrying for stone to make wheels, Berbers cut an entrance through the other end of the rock, tapping into the natural cavern that extended more than 18 miles to the Sea of Gibraltar. Three levels of the cave are open to visitors today, their walls carved into undulating waves by ancient tools. And up above a subterranean pool stands a statue of Hercules, bow drawn for battle.

Shoshi Parks | READ MORE

Shoshi Parks is an anthropologist and freelance writer whose work on history, travel, food and the natural world has appeared in Atlas Obscura, Afar, NPR and a variety of other outlets. She lives in California's Bay Area.