Infiltration is in no way a new concept — after all, who hasn’t clambered through an abandoned building, ducked under a fence to explore or slipped behind a barrier to see what’s there? In the ’60s and ’70s groups like the San Francisco Suicide Club began to codify the modern movement with organized guerrilla adventure groups. But in recent years, thanks in part to the community powers of the Web, the infiltration movement has grown in strength. It’s no longer a solitary pursuit; instead, you can join mailing lists, Usenet groups, countless webzines or even the Urban Exploration Web ring to swap tips, scout out good locations and meet fellow explorers. “I don’t think there could have been an urban exploration movement as there is now without the Web,” says Deyo. “It’s a good case study of what the Web can do sociologically; people all over the world send e-mails each and every day. We’ve even heard from someone who explored a nuclear submarine base in Russia.”

Although adventurers hail from any land in which abandoned buildings or underground tunnels can be found, there are particularly strong outposts in France (especially the Paris catacombs), Australia (thanks to its adventurous culture), Detroit (with a crumbling downtown full of abandoned buildings) and the East Coast of the United States. If you live in New York, you can join the Jinx Athenaeum Society, which holds monthly meetings promoting urban adventure, or participate in Solis’ Dark Passage infiltration parties.

Most infiltrators have been lifelong adventurers, but for many the first real step into the explorer underground is by going literally under the earth, into campus steam tunnels. Most campuses have extensive underground routes for Ethernet wiring and steam and water pipes. Despite the heat and cramped quarters, the pipes are big enough to host the curious students who climb through open grates to see what’s inside. On some campuses, such as Cal Tech, exploring the steam tunnels has become such an undergrad tradition that authorities turn a blind eye, also ignoring the poetry and artwork that students leave behind to mark their stays. (Wondering if your campus has steam tunnels and how to go about getting in? The
Urban Explorers Network compiles information about as many campuses as it can.)

“It’s kind of like punk rock — you’re into something not a lot of people are into,” says one student enrolled at Virginia Tech. He was initiated to the steam tunnels by an insider during his freshman year, and has since visited his campus library for maps and historical context; his Web site offers diaries and photos as well as advice to fellow students, although he keeps his name secret to avoid campus authorities. “It’s one of those weird paradoxes,” he says. “We want to be our own underground thing and yet we also want to brag about it and help others so they don’t get hurt or busted.”

Exploration of campus tunnels is a kind of gateway drug that leads infiltrators to more extensive tunnel networks — say, the New York subway system, which boasts level after level of abandoned yet oddly clean tunnels lit by eerie blue lights. Tunnels are probably the most common destination, since nearly every urban area is riddled with them. But Jinx’s Deyo and his co-editor, David Leibowitz, who began their magazine in 1996, pursue more lofty goals: Our “area of specialty among urban explorers is heights — a lot of groups like to go into the sewers and storm drains, but we really like to go onto rooftops and tops of bridges. I’ve always loved heights, getting that vantage point on the city that most people never get, having the whole city at your feet.” He prefers places like the Brooklyn Bridge and the rooftop of Grand Central Station, which have an “aesthetic tug … a certain epic quality.”

Infiltration is undoubtedly dangerous — there are always the very real risks of stumbling onto a live rail in a subway tunnel, falling off the top of a bridge or getting crushed under falling debris in a crumbling building. And there is the risk of getting caught, although most explorers I spoke with seemed relatively unconcerned about authorities. Of those I spoke to, only a few had been caught, and only Deyo had ever gotten in trouble. As a juvenile, he and Liebowitz climbed onto the roof of Grand Central Station and were immediately spied and apprehended — but even then Deyo merely got a ticket. “This is New York City and the cops have other concerns than some people who are basically participating in a minor victimless crime,” he shrugs.

Urban explorers admit that the appeal of infiltration is often about the thrill of being somewhere you are not supposed to be — or, as Solis puts it, of “confronting your fears, going into spaces that are dangerous and very creepy.” But despite the adrenaline rushes, many explorers say that it is also the poetry of this pursuit that draws them in.

Solis, for example, first began adventuring when she was a child in Hamburg, Germany, but it wasn’t until a few years ago that she started feeling compelled to document her explorations. She goes exploring several times a month and throws Dark Passage events — often based on a historical novel or film — in which she guides groups into forbidden places. Solis sees herself as “a little bit of an archaeologist, a little bit of a historian.” She specializes in the numerous abandoned lunatic asylums and hospitals that dot the Northeast, gothic monstrosities still cluttered with abandoned equipment, letters, furniture and records. “You are finding artifacts from a whole different way of life that you never would normally see,” she says. “I find file cabinets full of records and look at documents and try to figure out what went on in a place, reconstruct a story.”

The destinations are often doomed buildings on the brink of being demolished; many infiltrators feel driven to make a written or photographic record of historical places that will soon be lost forever. Photographer Shaun O’Boyle, whose Modern Ruins Web site is full of stunningly evocative images of abandoned hospitals, shipyards and factories, believes that “ruined buildings have an interest that goes beyond any interest that building may have had when it was occupied. It has become abandoned space; it no longer functions as it was designed to. The building is no longer sheltering anyone. The slow crumbling and decay make it less and less like architecture and more and more like shapes and forms, masses and planes for their own sake, much like sculpture.”

The infiltrators are not preservationists, however; rather, they are observers and chroniclers. Kevin Walsh, a 43-year-old copywriter for Macy’s, maintains the Forgotten New York site to document the smaller lost detritus of his lifelong home: lampposts, moldering signs and forgotten alleys that once were thriving roadways. It’s a trove of unnoticed ephemera: doorways in subway stations that lead nowhere, weed-encrusted station houses on the abandoned Rockaway rail line, long-forgotten sidewalk art. “I want to get there before the city notices that they are there and gets rid of them,” he says. “That’s why they’re still there, because people don’t notice them.”

Many infiltrators shy away from press coverage — such as Ninjalicious, the infamous founder of Infiltration.org and one of the movement’s heroes — for fear of trouble with authorities or encouraging too many newbies. But those like Solis and Deyo want to convey the message that the movement isn’t about crazy kids breaking, entering and vandalizing; after all, only a certain kind of person would dare to venture into the blackened basement of an abandoned lunatic asylum and brave the invisible ghosts simply to observe and understand.

Perhaps that person is just a little bit crazy, but the urban explorers have a unique perspective on the places around them. Consider them the secret keepers of the cities, above and below the ground. As Deyo puts it, “People have their own lives to lead and don’t feel much of a need to look up at architecture, which is a shame and is part of the reason why we’re doing it — it forces us, if no one else, to view the city as more than just a milieu for the mundane aspects of our lives, a place to work and live. It’s also an environment, and like any environment it can be explored.”