Caves, mines and catacombs: a journey through underground Europe

BarcelonaThere is a Europe that cannot be seen with the naked eye. It has no golden domes or flower-filled balconies, but it hides salt sculptures, inland rivers, and galleries that delve into the bowels of the continent. It is a subterranean Europe, dark, but fascinating, full of caves that resemble Gothic palaces, abandoned mines converted into living museums, and catacombs where the murmur of the centuries still resonates.

This is a journey downwards, literally. A descent that takes us to discover the other side of the landscape: the one not illuminated by the sun, but which shines with its own light. In this parallel world, time is measured in layers of rock, sediment, and legends. We find the natural art of stalactites, the scars of mining exploitation, and even the invisible traces of beliefs and rituals from millennia ago. Because beneath our feet, Europe preserves its deepest memory: the one that can be breathed between damp walls and dense silence.

To make this trip, we need very little: a headlamp, good shoes, and a deep breath to let ourselves be amazed by a mysterious Europe filled with stalactites, endless corridors, and secrets waiting to be discovered. Will you join us?

Beneath the frenetic asphalt of Rome lies a fascinating and funereal universe: dozens of kilometers of catacombs excavated between the 1st and 4th centuries. On the margins of ancient Roman roads, such as the Via Appia and the Via Nomentana, this subterranean labyrinth preserves thousands of tombs and unique witnesses to the funerary rituals of the early Christian and Jewish communities. Of the more than sixty catacombs located, only five can be visited today: San Callisto, San Sebastiano, Domitilla, Priscilla, and Santa Agnès. Frescoes, crypts, and decorated ossuaries speak of a time of faith, persecution, and mystery, where the remains of martyrs, faithful, and even sixteen popes rest. Some galleries remain unexplored, as if Rome held its most ancient secrets in the heart of the earth.

Thirty-three meters underground, in the heart of Picardy, lies a labyrinth of galleries that for centuries offered refuge to the inhabitants of Naours. Over 3,000 people found shelter there. In 1887, Abbot Ernest Danicourt rediscovered this forgotten space and opened it to the public. A museum recreating traditional Picardy trades.

Deep underground on the Royal Mile, Edinburgh's historic heart, we find Mary King's Close, a 17th-century street, closed off, forgotten, and literally swallowed up by the city's growth. It's the only street preserved from that time, revealing the darkest and most fascinating side of the Scottish capital. Former residents, epidemics, superstitions, and a city that grew upward while burying its most disadvantaged. Now, actors in costume and mysterious nighttime excursions bring this labyrinth of a cobblestone past to life. These dramatized, often candlelit tours will take you through chambers and corridors filled with memories—and the occasional haunting shadow. Whether you're drawn to urban history or a thrill seeker, this is a journey into the past that won't be easily forgotten.

Halfway between science and fantasy, Iceland hides a unique experience: entering a volcano. Thríhnúkagígur—a name that means three-peaked crater—is the only visitable magma chamber on the planet. Just half an hour from Reykjavik, it's a volcano that erupted 4,000 years ago and, inexplicably, left its chamber empty without the interior cavity collapsing after the lava flowed out. Now, with no risk of erupting again, and thanks to a metal structure that descends like a mine elevator, you can descend 120 meters into the bowels of the Earth. There, a gigantic cave awaits you, filled with walls painted in yellows, oranges, reds, and greens. A natural and vivid palette that seems straight out of a geological dream. It's a unique experience that could have come straight out of a Jules Verne book. But it's not fiction; just go to Iceland to make it possible. However, access is limited to the summer months.

Near Krakow, just 14 kilometers from the historic center, a secret and resplendent world opens up, seemingly straight out of a fairy tale: the Wieliczka Salt Mines. Operating since the 13th century, these tunnels, over 300 kilometers long and 327 meters deep, form a true underground salt city. Endless corridors, sculptures that shine like marble, translucent walls, and a microclimate with healing properties will surround you when you visit. The greatest surprise will come at the heart of the mine: St. Kinga's Chapel, a majestic church carved out of salt, with stained-glass windows, altarpieces, and lights that hang like frozen stars. Recognized as a UNESCO World Heritage Site, Wieliczka is much more than just an old mining operation: it is a sanctuary, a collective work of art, and proof that even in the bowels of the Earth, beauty and spirituality can be built.

Known as the world of the ice giantsEisriesenwelt is the world's largest ice cave. A labyrinth of more than 40 kilometers of underground galleries where frozen water has sculpted shimmering walls, colossal figures, and stalactites deep within the Tennengebirge massif, about 40 km south of Salzburg. To reach it, you must take a cable car and climb 1,400 steps to the mouth of the cave, where you will be greeted by a carbide light to illuminate your journey. Inside, the flickering light will reveal landscapes that change with each season and sub-zero temperatures year-round. It's only open to visitors between May and October, but the experience of walking inside the eternal ice is worth every step. A journey to the cold heart of the Earth.

In the basements of the German capital lies a parallel world of secret passageways, air-raid shelters, and escape tunnels that played a key role during World War II and the Cold War. And it's thanks to the Berliner Unterwelten association that this submerged past is open to visitors today. On its most famous tour, you can enter an original World War II bunker located beneath Gesundbrunnen station: a concrete labyrinth that housed up to 1,300 people during the bombings. You can still see original artifacts, inscriptions on walls, and rooms that have remained frozen in time. And that's just the beginning. Other routes explore former railway tunnels converted into nuclear bunkers during the Cold War, abandoned subway stations, or corridors excavated to help people cross the Wall. An immersive and surprising experience that invites you to look at Berlin through new eyes.