The Allure of the Underground: A Night in the Paris Catacombs part 2

In this three-part blog series, I explore the fascinating Paris Catacombs, starting with the official tour and venturing into the lesser-known, hidden sections of the underground. From the meticulously arranged ossuaries to the unique charm of the unofficial galleries, join me as I uncover the history, beauty, and quiet intrigue of this remarkable world beneath the streets of Paris.

I prepared thoroughly for my first visit to the unofficial catacombs of Paris, carefully studying the map provided by our guide to ensure I could navigate out alone if necessary. Still, no amount of planning can match the insight and perspective gained from living the experience firsthand. I have a vivid imagination and a healthy respect for the unknown, but I’m equally driven by a determination to face challenges and push beyond my comfort zone.

Our group of seven gathers on a chilly Saturday morning near our planned entry point, located in a railway tunnel. The dress code prioritizes practicality over style - waders, dry bags, and sturdy footwear are the essentials. Our entrance is a narrow passage through a small opening beside the tracks, functioning as a drainage canal. Almost immediately, we wade into cold, ankle-deep water, which quickly proves to be a constant companion in these tunnels. With headlamps cutting through the darkness, we set off down the long, shadowy corridor ahead - a path leading straight into the unknown.

The path we’re following is one of the catacombs’ “main highways,” a well-traveled route marked by graffiti that stretches across the walls. We’re now deep underground—about 30 meters below the surface—with anything but solid ground above. Overhead, the faint hum of passing metro trains occasionally vibrates through the earth, while the city’s sprawling sewer network flows silently above, a distant reminder of the bustling life just out of reach.

The corridor stretches endlessly ahead, the water mostly knee-deep but occasionally rising to our thighs. While water in the catacombs is often crystal clear, our steps stir up limestone dust, transforming it into a cloudy, muddy haze. This obscures the floor, concealing ridges, rocks, and other hidden obstacles. Tripping becomes a constant hazard—a minor inconvenience in other circumstances, but a significant challenge when carrying delicate equipment like a camera.

The water level in the tunnels varied. Here I am moving forvard in tight-deep water. Video by Ksenia.

As we press on, we’re forced to revise our original plan. Vadim, the tallest in our group, ventures ahead to test the depth of one corridor. When the water rises to his chest, it becomes clear that the passage is impassable - especially with our gear. Swimming isn’t an option, so we retrace our steps and begin the search for an alternative route.

The tunnels shift dramatically in shape, width, and height as we move forward. We’re thoroughly enjoying our underground exploration, pausing now and then to examine the rare street signs we encounter. Though few and far between, these signs reveal the streets above, creating a surreal link to the bustling city overhead. Adding to the intrigue, pixel art tile mosaics - familiar sights on Parisian buildings - make unexpected appearances down here as well, their small, whimsical designs occasionally decorating the catacomb walls.

Our guide adds to the experience with his knowledge and enthusiasm. It’s clear he’s passionate about the catacombs, even though he’s not yet vastly experienced - this is his eleventh trip underground.

As we explore, we pass wells, carvings, and even statues. Among the underground landmarks are The Beach, an eerie “sand beach,” and The Mineralogical Office, where stone steps once showcased mineral samples for inspectors during the mining era. Then there’s The Crypt, a small gallery reached by descending a narrow, curved staircase adorned with intricate carvings. Of course, everyone ventures here hoping to see bones, and we’re not disappointed. We come across beautifully arranged bone structures, with carefully stacked piles of femurs and skulls - and even a bone waterfall!

A bone waterfall is a striking formation created when bones were dropped from a hatch in the ground above, directly into the catacombs. Over time, these bones accumulated into a cascade-like structure. The larger, more prominent bones, such as skulls and femurs, often rest on the surface, while smaller and less noticeable bones form the dense supporting layers beneath. The result is a chaotic yet oddly structured pile, shaped by both gravity and the sheer volume of remains deposited from above.

Ksenia, Vadim and the Bone Waterfall

As we make our way through the tunnels, we occasionally encounter others, exchanging quick “Bonjours” or “Saluts” before continuing on. Most of these meetings are brief and uneventful - just fleeting shadows passing in the dark. But then, out of nowhere, an explosive bark shatters the quiet, echoing through the passageways like a small detonation. The sound is startlingly close, just around the corner, and for a moment, we freeze. The thought of coming face-to-face with an aggressive dog in the tight, confined space is enough to make us retreat without hesitation. Abandoning our planned route, we quickly backtrack to find another way.

Time distorts underground, with hours slipping by unnoticed as we explore. At one point, we pause in a gallery where stone ledges along the walls provide convenient benches. Curious to experience the depths of absolute darkness, we briefly switch off our headlamps, plunging ourselves into a damp, dense blackness. The darkness feels almost tangible, as if the air itself is pressing in on us. After about ten minutes in this small gallery, the sensation of thin air becomes noticeable - too little oxygen and just a bit too much carbon dioxide. It becomes clear that this space, while intriguing, is too confined for seven people to remain comfortably for long.

When stepping into this hidden world to explore, it’s crucial to prepare for the unexpected. A simple detour or the rare but serious possibility of a tunnel collapse can easily extend your visit. Reliable lighting is non-negotiable: we carried headlamps, extra batteries, and a power bank, along with chemical light sticks as fail-safes. Water, some food, and identity cards (in case of contact with the police) are equally essential. A map - whether on paper or saved as an image on your phone - is a must, as there is absolutely no signal underground.

Keep in mind that everything you bring should be lightweight and compact. You’ll need to carry it for hours, so packing wisely is key to ensuring both comfort and mobility during your exploration.

You need to dress wisely. The catacombs maintain a steady temperature of 13°C, which can feel warm enough in winter as long as you keep moving - even when wet. However, it’s always smart to prepare for colder conditions in case something unexpected happens. Quick-drying clothing is essential, and anything that becomes heavy or uncomfortable when wet should be avoided entirely. A little foresight in your clothing choices can make all the difference in staying comfortable and mobile during your exploration.

One of the greatest hazards is hitting your head on the rough, stony ceilings. At the very least, a beanie offers minimal protection, but a helmet is far better and highly recommended.

In hindsight, we might have been overly cautious with our preparations, but perhaps that thoroughness is exactly why everything went so smoothly. Having no major challenges to face is the best outcome, and good preparation is what makes it possible. Remember, you need to be able to carry all your gear comfortably for hours, so pack wisely.

We were mindful of the time, knowing that our exit would require retracing our steps back to the same point where we had entered, as planned. This meant allowing for roughly the same amount of time to return, though likely a bit less since we had paused frequently on our way in to explore galleries and landmarks. After hours underground, we decided we’d seen enough bones for one trip and began the journey back. The return took about two hours, and as we approached the surface, the air grew noticeably fresher and colder - almost startling after the damp, heavy stillness below. The water we waded through became progressively colder the closer we got to the exit, a chilling reminder of the transition from the subterranean world to the open air above.

Emerging from the tunnel, we were invigorated by the rush of cold, fresh air after six unforgettable hours beneath the city. Exploring Paris’s hidden underground world had left us thrilled and in awe. Thanks to the whole amazing team who made this unforgettable journey possible! Thank you  Kimmo, Niko, Ksenia, and Vadim, and a special thanks to our great guide and his brother, whose names I’ll keep as my secret.