The Ukrainian port city of Odesa sits atop a labyrinth of catacombs—technically, limestone quarries—which constitute perhaps the world’s largest network of urban tunnels, extending ten stories deep and tracing some fifteen hundred miles beneath the streets. Ever since the nineteenth century, as stonecutters mined the passages to build the city, locals have regarded these voids as a realm of mystery and peril. They have been a setting for both banditry—traffickers smuggled stolen goods through the quarries; fugitives dodged pursuers in the darkness—and heroism. During the Second World War, when the city was placed under siege by the Nazis, Soviet rebels used the tunnels as a secret headquarters. These days, a mysterious crack may open in the sidewalk, and Odesans will experience a sudden awareness of the hollows beneath their feet. But very few ever venture beneath the surface.
Roman Mauser, a thirty-one-year-old electrical engineer from Odesa, began exploring the catacombs as a teen-ager, climbing down metal hatches in the street and spending hours wandering the passageways by headlamp. He discovered a world of forgotten infrastructure: drainage systems, moldering command centers, Soviet bomb shelters. Alongside a team of fellow-explorers, he opened a tour business where he guided people through the catacombs. On YouTube, he launched a channel on which he documented his expeditions. Episodes include a journey through a lattice of drain pipes and an investigation of mysterious inscriptions recorded on catacomb walls.
In early March, as the Russian navy amassed a flotilla of warships in Odesa’s harbor, Mauser’s hobby became a wartime enterprise. Residents had become alarmed by the city’s critical shortage of functional air-raid shelters. When Russian fighters dropped bombs on Kyiv, thousands of residents took cover in the city’s metro system. Odesa does not have a metro. Russia was poised to lob cruise missiles into the city; in the event of a heavy assault, Odesans would need someplace to wait out the bombardment. Throughout the city, military-age citizens were volunteering to man checkpoints and build barricades. Mauser, round-faced and bespectacled, with a poet’s bearing, joined dozens of civilian explorers in an effort to bolster Odesa’s underground defenses.
On one of his first missions, he trekked with a band of men through a warren of limestone tunnels beneath the historic neighborhood of Moldavanka. Sweeping their flashlight beams through the dark, the group arrived at the door of an old bomb shelter. Peering inside, they found rusted walls, piles of rubble, and puddles of stagnant water. The shelter had been built just after the Second World War, when Ukraine was part of the Soviet Union; nearly a hundred feet beneath street level, it could protect hundreds of occupants from even the most forceful air strike.
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Mauser and the others worked for days. They cleared debris, painted walls, installed makeshift benches and cots, and stockpiled water. Mauser ran electrical cables through the passageways and rigged lights along the ceiling. Up on street level, the explorers met with residents from the neighborhood and instructed them on how to take cover. For most Odesans, Mauser told me, the catacombs had always been a distant, almost imaginary place; now the tunnels were entering the city’s consciousness in the most urgent way. “We need to prepare people,” he said. “In any attack on our city, the catacombs can save us.”
I met Mauser about a decade ago, when I was on a research fellowship for a book about underground space. I’d been in the field for several months, interviewing urban explorers roaming the sepulchres under Paris, archeologists excavating underground cities in Turkey, monks praying in caves in India. Odesa had not originally been on my list of destinations, but an explorer in Paris had rhapsodized about the city’s tunnels. In a map he showed me, Odesa’s underground resembled the intricate folds of the human brain.
Mauser had been referred to me by a friend of a friend. When he arrived to pick me up at my hotel—nineteen years old, with gentle eyes and peach fuzz on his chin—he was wearing military-issue coveralls that bore the insignia of the Soviet hammer and sickle. That night, while Odesans gathered in cafés along the shore of the Black Sea, Mauser and another catacomb explorer, named Boris, led me beneath the streets of the city. We splashed down into a soggy passage, our voices echoing fractally in the dark. Roots spidered down from the ceiling; everything smelled of chalky earth.
It was clear from the first moments how much Mauser loved his city’s underground. He spoke English in a percussive Slavic accent that made everything sound like a pronouncement of wonder. “Very fucking amazing!” he would exclaim, as we turned down new passages or emerged into unseen chambers. Down one tunnel, we cast our lights over a ceiling that was ridged with brick arches like the ribs of a whale skeleton. In another, we came across a kind of subterranean pond, eerily glassy in the unchanging conditions. At one point, we had been roaming through the dark for several hours when Mauser ducked into a side tunnel and emerged with an old canteen. “From Soviet times!” he said brightly.
To enter any underground environment—pitch-dark, silent, cut off from natural rhythms—is to step outside time. In the catacombs of Odesa, it was as though history had become fossilized. Remnants of the Soviet Union were everywhere. In addition to bunkers and infrastructure, explorers like Mauser would come upon old military encampments: caches of rifles and grenades and helmets scattered over the ground, as though a platoon might return at any moment. (Mauser had a whole collection of Soviet relics, including gas masks, hand grenades, and munitions shells.) They’d find century-old poems inscribed on the walls in Cyrillic. Rumors swirled of a chamber where young Communists conspired against the Tsar before the Revolution. It was said that explorers sometimes found the remains of fallen Soviet soldiers.
For Mauser, who was born just before the dissolution of the Soviet Union, each descent was a communion with a complicated history. As we wandered through the dark, he spoke of his ancestors, including his great-grandfather, who’d served in the Soviet military and marched on Berlin at the end of the Second World War. He talked about his relationship with Russia, which had given rise to a kind of split identity within him. Mauser was Ukrainian in nationality, but Russian in ethnicity. He was fluent in Ukrainian, but formed thoughts in Russian. “Russia is like the big brother of Ukraine,” he told me at the time. “We love him, but he sometimes can be an asshole.” Now, he says, any sympathies he once felt for Russia are gone: “Even such thoughts are traumatic to me.”
A few days later, on Mauser’s recommendation, I visited Nerubayske, a village to the north of Odesa where a section of catacombs had been opened to the public as the Museum of Partisan Glory. Several stories underground, I wandered dank, dimly lit tunnels that had the feeling of a lost troglodyte city. One stony chamber had been retrofitted as a kitchen, complete with a cooking stove and shelves for pots. Down another passage was a bedroom, with bunk beds carved out of the walls. Next door, a sort of armory was stacked with rusted weapons.
From a series of placards, I pieced together a story often told in Odesa. In August of 1941, during the Siege of Odesa, when Nazi German and Romanian planes began bombarding the city, scores of Soviet resistance fighters descended into the catacombs. They spent months beneath the boots of their occupiers, smuggling intelligence and supplies between strategic points and transporting injured comrades. From time to time, they surfaced to ambush Nazi soldiers. One cell, led by a partisan fighter named Vladimir Molodtsov, was said to have derailed two Nazi military trains and killed three hundred soldiers. The occupiers attempted to counter the partisans by gassing the tunnels and sealing off access points to entomb them, but the rebels persisted. Civilians, meanwhile, lowered buckets of food and supplies down wells, under the guise of collecting water. When the Red Army returned to Odesa in April, 1944, some of the rebel forces were still underground: pale, malnourished, but attempting to hold their city from below. Their heroism was celebrated in a made-for-TV movie, “Katacomby,” which became a beloved founding text for Odesa’s young catacomb explorers.
On one of my last nights in Odesa, Mauser rounded up a few explorer friends and we camped out for a night in the catacombs. We gathered in a high-ceilinged chamber where stone slabs had been dragged into place as benches and tables. We lit tea candles and snacked on cheese and fruit. Then we set off trekking through the tunnels, wriggling in and out of tight passageways, clambering over rockfall, searching for links to unexplored sections of the network. My knees grew sore, my neck stiff from stooping, but Mauser and the others were indefatigable. As we hiked, they found charcoal messages recorded on the walls in Cyrillic, among them the names of Soviet partisans who, generations ago, with their city under siege, had stalked these same passageways. At the end of the night, we zipped into our sleeping bags, blew out the candles, and lay in the dark, whispering in a mix of Ukrainian, Russian, and English, until we all fell asleep.
Before I left for my flight, Mauser met me on the cobblestones outside my hotel. As a parting gift, he brought a prized relic from his collection: an old Soviet gas mask, which I still have on a shelf at home.
These days, when Mauser is not working in the catacombs, he is elsewhere volunteering or at home in his apartment. Many of his friends left the country in the early days of the war, and he spends much of his free time alone. In our correspondence, he sometimes sounds resolute: “We are preparing and waiting for this bastard putin to attack us.” “We are united as fuck!” Other times, he sounds adrift. Like all young Ukrainians, Mauser is seeing images of city blocks reduced to smoking rubble and trying to envision the future of his country. At the same time, he is clearly grappling with his relationship to the past. In one message, he enclosed side-by-side photographs of the city’s landmark opera and ballet theatre: a black-and-white image from 1941, a color one from 2022. The images are almost identical, the theatre barricaded behind sandbag walls and anti-tank obstacles.
The resonance is particularly disorienting for Mauser, who has spent years exploring underneath the city, immersing himself in the very history that is now reëmerging. In a recent YouTube video, uploaded as shelling began in Odesa, Mauser crouches in the dim light of a bunker. He looks just how I remember him, the same serious, sensitive eyes. Levelling his stare at the camera, he addresses an imaginary Russian audience. “Many of us have Russian roots, like my ancestors. My great-grandfather took Berlin,” he says, with desperation edging into his voice. “And you will call me a Nazi.”
In our last conversation, Mauser had just emerged from a long day working beneath the city. He thought that the worst was over, that Putin would turn away from Odesa. But he sounded wary. Down the coast, in Mariupol, Russian bombs had just laid waste to a theatre, killing about three hundred people, according to local officials. In the nearby city of Mykolaiv, a rocket had blown a hole through the region’s administrative headquarters. Warships were still anchored off the coast of Odesa, and the peals of daily air-raid sirens echoed throughout the city. Mauser had begun work on new underground defense projects. After a while, he told me that he was too tired to talk anymore. I pictured him in his apartment, surrounded by Soviet relics. I told him that what he was doing to protect Odesa, holding his city from below, was heroic. “No one here is talking about heroes,” he said. “We only wish this wasn’t happening.”