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Spelunking under New York

  • Written by  Steve Duncan
  • Published in Explorers
Built in 1842, the Croton aqueduct was New York’s first major water-supply tunnel Built in 1842, the Croton aqueduct was New York’s first major water-supply tunnel Steve Duncan
20 May
Spelunking? It’s what we would call caving or potholing. And urban spelunking is what it sounds like: exploring cities’ underground infrastructures. Steve Duncan describes the highs and lows, and outlines the kit you’ll need to mount your own metropolitan subterranean expedition

It was the start of a week-long expedition through New York City’s underground and I had already ripped a hole in my chest waders. Four metres beneath Tibbett Avenue in the Bronx and the water coursing through the tunnel was cold enough to make my right foot go numb. I was in a 19th century brick tunnel with my expedition partner Erling Kagge. The water around us had once flowed above ground as a small river. Tibbett’s Brook had powered the water mills in the region before it was coaxed into the brick drain tunnel a little over a century ago. Climbing down the drain’s rock wall and into the tunnel wearing heavy chest waders with integrated boots had been more challenging than I’d expected. As I slid down, something caught the right leg of my waders and punctured the tough rubber.

I didn’t want to complain about my cold feet to Erling, a polar explorer who once spent the better part of two months walking solo to the South Pole. But after a little while I couldn’t think about anything else. Erling has a nearly superhuman ability to be cheerful in any circumstance. He listened to me while we took a break, standing in the flowing water, the absolute darkness of the tunnel alleviated only by our headlamps. He nodded once or twice and then admitted that he had a hole in his own waders too. ‘Well, Steve,’ he pointed out, ‘It is very cold water. But you said we only have a short distance to go in this underground river before we join the sewer. Maybe the water will be warmer in the sewer?’

He was right, of course. Another few minutes of wading through the small tunnel and we came to where the stream of water flowed into the much larger mainline combined sewer tunnel. (A combined sewer is capable of carrying storm drainage as well as everyday sanitary sewage.) The changes were sudden: warmth and humidity in the air, the stench of sewage, and plenty of decomposing organic material. The underground stream water had been clear. Here it was a fetid brown. Decomposition creates heat, and the organic waste in this sewer – even when diluted with street runoff and the flow from underground streams like the one we’d followed to get here – made it considerably warmer than the liquid we had already waded through. Feeling began to return to my foot.

I did not want to think about what was sloshing around in my boot, and so I let myself be distracted by my environs. The space we were in was as magnificent as any surface architecture. Built in 1895, it consisted of a beautiful double-arched brick tunnel with two parallel channels about three metres high and four metres wide. Occasionally we passed stalactites and fantastic patterns of flowstone that had congealed on the brickwork over the last hundred years.

amtrakThe West Side Line commuter train tunnel in New York (Image: Steve Duncan)


Erling had proposed this expedition the previous summer. His idea was to spend a week trekking through underground New York City in December. Erling came to me because I have been exploring New York’s underground infrastructure for more than a decade.

What gear does the urban spelunker need? The answer is complicated because it’s not just one environment but a wide set of different environments that each have their own challenges. That’s especially true when you visit different cities and discover that a metropolis’ underground is as unique as the municipality it supports.

In Los Angeles my underground explorations have taken me through the city’s network of storm drains. These tunnels were built to void the brief yet heavy annual spring rains that would otherwise flood the city. For the rest of the year the flow is barely ankle-deep. And unlike New York’s system, these drains are completely separate from the sewers so the water is relatively clean. My gear for those explorations had been simple: old hiking boots or heavy-duty neoprene scuba boots with a thick rubber sole. I usually wore a soft shell jacket zipped up all the way up to my chin to provide psychological protection from the spiders and their webs that line the manhole shafts.

In Paris, I’ve spent many days in the so-called ‘catacombs’, a roughly 200-kilometre network of ancient limestone quarry tunnels that were dug out between the 13th and 18th centuries. Some sections of the catacombs became ossuaries in the 18th and 19th centuries. Other segments were converted into bunkers during the Second World War.

Over the years, some sections of Paris’ tunnels have turned into a wonderland of graffiti layered over the ancient stonework. This is where catacomb explorers, known as ‘cataphiles’, hold late-night picnics. Many cataphiles use carbide lanterns, which emit a warm light capable of illuminating entire rooms. Chain-smoking French cataphiles use the flame from the carbide to light their Gauloises. On multi-day explorations, an easy way to sleep is to hang a hammock from hooks that industrious cataphiles have installed in select chambers.

In London, the most interesting spaces can be found in the Victorian-era sewer system. This incredible subterranean world of hand-laid brick tunnels contains the numerous small streams and rivers that, prior to the 18th century, flowed above ground as tributaries to the Thames. The potential for flammable gases in sewers means that open-flame carbide lamps can be dangerous. Sealed LED headlamps are much safer. In addition, it is always a good idea to carry a multi-gas meter in any active sewer. These devices constantly test for Hydrogen Sulfide (H2S), Carbon Monoxide (CO) and any traces of flammable gases. They also monitor oxygen levels. Hip or chest-high waders connected to tough rubber boots are vital in London. Without this type of protective gear the capital’s notoriously deep sewage would be beyond discouraging.

New York City’s subterranean infrastructure includes subway tunnels, combined sewers, steam tunnels, underground rivers, and abandoned freight train and subway tunnels. Erling and I planned to visit all of these types of passages. We knew that the most challenging environment would be the combined sewer. Although chest-high waders were our most important piece of kit with regards to comfort, the multi-gas meters were the most vital to our safety.

Tough gloves are also essential, even in storm drains where the water is theoretically cleaner than in the sewers. I learned this lesson a few years ago when I had a minor fall in an underground river and punctured my hand on some debris. 12 hours later and I was in hospital with a blood infection so severe that I almost lost my arm.

The rest of our gear was more general: headlamps with a couple of back-up lights, warm clothes and good boots. The single heaviest item we carried for the trip was a manhole hook. By the time we added in camping gear we each had a pack that was so heavy and bulky that it was difficult to fit it down the manholes.

sawmillThe Sawmill River in Yonkers, one of many natural waterways that were covered over as New York developed in the 19th century (Image: Steve Duncan)


It was late at night by the time Erling and I had finished the first leg of our trip through the underground river and the sewer. We were sodden with sewage under our useless waders. At our exit manhole we raised a small signal flag through the ventilation hole in the cover as a sign to the lookout we’d stationed there. He blocked off the area, gave us the all-clear, and we emerged into the winter air.

Cold and wet, we headed into the steam tunnels beneath Columbia University. In the 1880s, New York was the first major city in the world to develop district steam heating, which is widely used for institutional campuses like universities. Superheated steam from a central plant is distributed along pipes that run through underground utility tunnels. To this day, the steam coursing through the pipes heats the campus above, which means that the tunnels are also quite warm. I was grateful for the heat as we settled down to sleep by the steam pipes. Erling protested: it was too hot for the polar explorer.

We took a break from our expedition the next day to go shopping for new waders. One of the things that makes urban exploration easier than wilderness expeditions is that you’re never too far from supplies.

By the third day of the journey we were walking through abandoned subway and railroad tunnels that are now the residences of the ‘mole people’, who are homeless individuals who have found refuge underground. Ever the gentlemen, Erling carried a birthday cake to Brooklyn, a tunnel-dwelling woman I had met several years earlier. It was her 50th birthday. After the party we pitched our camp next to the home where she has lived since 1982.

Staying underground with a woman who has hardly any possessions except that which she has rescued from the trash, I was reminded that sometimes gear isn’t the most important thing for adventures. Equipment can make you more comfortable, and sometimes it can save your life. But for going underground, the most important thing is a willingness to meet your environment: to get wet, dirty, and cold, and to slog through whatever may lie in front of you for the simple reward of having seen your city from an entirely new angle.


Although I didn’t know it when I started, photographing the hidden infrastructure beneath the city follows in the footsteps of the 19th century French photographer Felix Nadar. Nadar was the first photographer to use electric lighting for illumination. He carried hundreds of pounds of primitive batteries into the sewers of Paris to power the electric arc lights he used to photograph the tunnels. When Nadar began the project in 1858, Parisian sewers were newly-constructed, a veritable wonder of the world. His laborious work showed a wider audience a glimpse of the magnificent but hidden engineering underlying the modernising city. The great social critic Walter Benjamin would write decades later that Nadar’s photos marked the ‘first time the camera lens was used as a means of exploration’.

My lights and cameras weigh less and are more efficient than the equipment Nadar used. But the thrill of making images that reveal a place shrouded in darkness remains. My favourite technique for taking pictures in tunnels – and one that involves minimal equipment – is ‘light painting’. With the camera mounted on a sturdy tripod and with the shutter open for a long exposure, it is possible to paint light into the scene using a single bright torch or a combination of a few colour-matched weaker ones.


Steve Duncan takes a combination of specialist gear to keep him safe, clean, warm and dry, and more everyday equipment that helps him make the most of his time below the surface...

1. Waderstuff

Orvis Clearwater Endura Breathable Bootfoot Waders – £189; 2.1 kilograms

Inexpensive PVC thigh-waders are fine most of the time. But for high water, nothing can beat these lightweight chest waders. Erling and I began our NYC expedition with heavier rubber waders but the Orvis waders ultimately proved to be longer-lasting.

2. Gloves

Petzl Cordex Plus Rope Gloves – £39; 252 grams

A cut or scrape in the urban environment can lead to a serious infection. Yet climbing on rough concrete or bracing your hand against a wall as you walk through a tunnel wears out most gloves in a few months. These double-layered leather gloves are the only ones I’ve used that are still comfortable when wet and which last me more than a year.

3. Manhole Lifter

6" Closed Handle Manhole Cover Keys (for UK-style manholes) – £8; 1.5 kilograms

Manhole lifters or manhole keys differ by country so find the appropriate one for your next destination. In the US, the standard format is a hook that catches the edge of the manhole cover. In most of Europe, the key fits into a small slot in the manhole cover which is then turned in order to catch and pull up.

4. Headtorch

Petzl Tikka XP2 – £45; 88 grams

Light is the most important thing you can have underground. Any bright headlamp will do. This headtorch isn’t the brightest model available, but it is easy to slip in a pocket and is worth a mention because of the red LED option which helps you retain your night vision. Red is less visible from a distance, which is perfect if you’d rather not be noticed.

5. Trousers

Patagonia Men’s Nomader Pants – £70; 363 grams

Clothes for urban exploration need to walk the fine line between something you can wear into the nastiest environments, and something that still looks respectable when you rejoin polite society. After all, you don’t want to look like something that just crawled out of a sewer, even if you just did. These quick-drying trousers are unlikely to tear in embarrassing places when you’re climbing over a fence.

6. Multi-Gas Detector

MSA Altair 4x – £479; 210 grams

Gas detectors are the most vital piece of safety equipment when entering man-made confined spaces with potentially poisonous atmospheres. The Altair is one of the easiest to use and least expensive models. Whatever device you get, be sure that it tests for Hydrogen Sulfide (H2S), Carbon Monoxide (CO), Lower Explosive Limit of flammable gases (LEL) and Oxygen content (02).

7. Rucksack

Black Diamond Demon Pack – £90; 1.23 kg

The Demon is a good all-around choice. Its simple features make it easy to clean and the main pocket is big enough to hold camera gear, a small tripod, flashlights, dry socks and perhaps a pair of lightweight hip-waders. However, if you need to squeeze through particularly tight tunnels a smaller pack would be a better choice.

8. Hammock

Eno Double Nest Hammock – £60; 566 grams

My favorite place to spend a few days under a city is the Paris catacombs. The best way to sleep there is in a hammock strung between hooks that the cataphiles have installed in a few hidden rooms off the old quarry tunnels. If you try sleeping on the ground as I did on my first visit, you’ll discover that the cold floor sucks the heat from your body so quickly that you’re left wondering whether you’ll ever make it back to the surface.

9. Waterproof mobile phone case

Lifeproof iPhone Case – £50; 28 grams

I make great use of the GPS and map features on my iPhone to tag possible manhole entrances and to review satellite images. Yet nothing ruins a day like falling in a slippery drain and soaking your phone. This waterproof case takes away a lot of worry. A cheaper alternative is a Ziploc bag: take one for your wallet as well.

10. Tripod

Velbon MAXi Tripod – from £70; from 580 grams

The Velbon MAXi, LUXi and REXi tripods have twistlock legs that collapse into surprisingly short packages. I have found them to be the best travel tripods for the price. Although lightweight tripods are more unstable than heavier models, there’s usually no wind to shake the camera in a tunnel. I replaced the supplied Velbon pan/tilt head with a smaller and more secure Manfrotto Mini Ball Head.

Don’t forget…

…maps! Although exploring means going on journeys that often can’t be mapped out, check websites like www.catacombs.explographies.com (for information on the Paris catacombs). A little research can enrich any exploration by providing some historical context.

Steve Duncan is an urban historian who has explored and photographed tunnels beneath dozens of cities in North America, Europe and Asia. www.undercitywebsite.blogspot.co.uk

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