The “finish” is maybe five feet away, but at this point it hardly matters.

I’m dangling 10 feet in the air, completely sapped of energy, and doing my best just to hold on as a razorlike burn courses through my forearms and shoulders. Below me, a fit young crowd has assembled—it’s the type of “grab life by the short hairs” scene reminiscent of a beer commercial—and I try to regain my focus as they offer words of encouragement. But the truth is, I can’t. Bizarrely, I’ve started laughing, as if in some state of fitness-inspired euphoria. If I were to fall and break my neck, I think to myself as the Black Keys come wafting up through the rafters, at least I’m not in a gym that’s playing “Uptown Funk.”

My fingers give out, and I fall backward for the fourth time today (by now, I’ve perfected my Hans Gruber–in–Die Hard impersonation), and I land gently on the soft padding below.

“Gravity—it’s the great equalizer, man,” says Mike Stewart, general manager of the Brooklyn Boulders climbing gyms in New York City and one of my climbing partners for the day. If you were looking to cast a movie about rock climbers, Stewart would be your guy. Cut and compact, with short, mussed brown hair, he has that halo of rugged outdoorsy-ness that gives you the impression he leads expeditions up Kilimanjaro on the weekends. “Gravity doesn’t care how much money you have, what school you went to, what demographic you are—it’s indiscriminate. You’re going to fail, and you’re going to fall.” Out of context it doesn’t sound like much of a pep talk, but sitting there on the padded floor, surrounded by climbers of all stripes and skill levels, it’s surprisingly motivational. There’s no shame in failing here.

In fact, it’s the failing part that keeps you coming back. I just wish I could fail at the level I used to. It’s been more than four years since I laid a chalky hand on a climbing wall, and my former skills have all but evaporated. “The sport can be pretty unforgiving in that respect,” says Luke Livesey, Brooklyn Boulders’ head climbing instructor. “If you don’t climb for even a few weeks, you really feel it when you come back.” Although I used to climb at an intermediate level, today I may as well be a beginner. I can feel it in my hands and forearms. I can especially feel it in my back—imagine doing 15 pullups and then immediately trying to hoist yourself up a rope, and that’s basically how the last third of any climb feels. But fortunately, in climbing, difficulty isn’t really a matter of the steepness of the grade; it’s the pattern and protrusion of holds that form what’s known as the route. My current white whale is this V3-grade zigzag of yellow lumps stretching just 15 feet in the air.

As I sit there and begin to recalculate my approach to the route, I notice, like everyone else in the enormous room, a microsize girl on a nearby, prohibitively difficult V9, who has apparently discovered some wizard’s spell for defying gravity, scurrying her way up an incline with the ease of an ant climbing a blade of grass. When no one’s paying attention, I quietly haul myself to my feet, reapply some chalk to my hands, and march back to the wall.

Calling rock climbing a sport is a disservice; it's more like an obsession. And for a long time I was among the obsessed.

Like a lot of male climbers out there, I first got into the sport because of a girl. It was her hobby, and she was consistently better at it than I was, which drove me to log serious hours inside dank and dark climbing gyms in hopes of impressing her. Admittedly, I never did meet her skill level, but I did get really fit as I tried.

But when I relocated to New York City—where big climbing gyms are outnumbered by vegan steak houses—I was forced to join a standard treadmill-and-free-weights gym.

That was four years ago.

Today, rock climbing—and the chic rock-climbing gym, in particular—is one of the fastest-growing fitness trends in the country. “Over the past three years we’ve had pretty much double-digit growth,” says Mike Helt, editor in chief of Climbing Business Journal. “Almost every state and almost every major metropolitan area has a climbing gym.” There’s Earth Treks in Maryland and Colorado, massive 28,500-plus-square-foot climbing and fitness gyms that offer hundreds of climbing routes to solve. Stone Summit in Atlanta features towering four-story climbing walls alongside gleaming, modern gym equipment and a rock slide. And then there’s Vertical Endeavors in Minnesota and Chicago, the biggest rock climbing gyms in the country with 45,000 square feet of climbing wall each.

But no other gym represents the new “climbing-gym lifestyle” quite like Brooklyn Boulders, with headquarters in Brooklyn but currently expanding all over the country. With its newly opened Queensbridge location in Long Island City, NY, the brand is doubling down on a strategy that has made rock climbing all the rage among a new breed of fitness junkies, namely millennials and Silicon Valley types. “Most people think in terms of work-live-play, in that order,” Stewart says. “But we prefer to think of it as play-live-work.” He says that’s a philosophy long embraced by the Facebooks and the Googles of the world, what with their expansive toy-and-amenity-festooned campuses that include rock-climbing walls amid conference rooms and cubicles. Even if you don’t work in Cupertino, he tells me, you can get that same experience at any Brooklyn Boulders.

“We saw that people would bring their work to the gym,” says Jeremy Balboni, who, along with Lance Pinn and Stephen Spaeth, founded the original Brooklyn Boulders in 2009. “They would work, they would climb, they would go back to work, but on, like, shitty little benches. They were just happy to be part of the environment, even if they weren’t climbing. That’s when we realized we’d created an environment where people just wanted to be.”

When they opened up an outpost in Somerville, MA, in 2013, they made sure to include both work and event space alongside the rock-climbing walls. And now, with Queensbridge, there are not only desks and work spaces and wi-fi, but also art on the walls, a café, and a glass-walled conference room—all meant to appeal to today’s growing band of coders, investors, and creative classes.

Of course, this is all a far cry from your standard climbing gyms of just a few years ago. When the first indoor rock-climbing gym opened in America in 1987, it was simply a place for outdoor climbers to keep fit during the winter when they weren’t scaling Half Dome during the summers. As the gyms proliferated, they remained little more than dark caves stuffed into industrial warehouses on the outskirts of town where hardcore climbers took the winter edge off. Even when the sport expanded in the early 2000s, climbing gyms stayed geared toward hardcore climbers.

“It’s easy to sell climbing to climbers,” says Mike Helt. “They’ll go to a dirtbag cave and climb, no problem. But to sell climbing to a non-climber takes a different approach.”

That approach is evident as I tour the new Brooklyn Boulders Queensbridge facility, where it feels as though I’m walking inside a pyramid. The space is gigantic, measuring 25,000 square feet. There’s a work space just past the front desk that Cyrena Lee, a Brooklyn Boulders employee, tells me will soon have overhead pullup bars. A short elevator ride takes us down to the main climbing floor, where pale wooden walls are adorned with holds that look like great gobs of rainbow-colored chewing gum. In the center are towering climbing walls with ropes dangling from the top like jungle vines. Down yet another floor there’s the glass-walled conference room intended to appeal to techies, a yoga studio, and an event space that has so far featured concerts, mixology classes, and a Ping-Pong tournament. There are even plans for hosting TED talks. Tucked inside both the men’s and women’s locker rooms are cedar-paneled saunas. There’s art on the walls—so far a couple of specially commissioned paintings by New York artist Shantell Martin, with more to come—and the place is drowning in sunlight. All I could think during my tour was that someone had figured out a brilliant way to cram the world’s coolest playground into a giant New York art gallery.

Like most climbing gyms, Brooklyn Boulders is broken into three areas for three different types of climbing: bouldering, top roping, and lead climbing. Both top roping and lead climbing involve ropes and a technique called belaying, in which one climber applies tension on one end of a rope to keep another climber on the other end from falling. Bouldering, on the other hand, is done without ropes and generally maxes out at a height of around 20 feet. The only equipment needed to boulder are a good pair of climbing shoes, a bag of chalk, and a padded floor to ease your falls.

In terms of difficulty, climbs are measured by grades—5.5 to 5.15 for rope climbing and V0 to V16 for bouldering. V0s and 5.5s are the beginner grades, essentially like climbing a wonky ladder designed by a drunk. V5s and 5.10s are intermediate, and anything above a V10 or 5.13 means you’re probably slinging webs and saving New Yorkers from costumed villains in your off hours.

One of the aspects of climbing that make it so addictive is that you can progress through the beginner grades pretty quickly. This is largely because you can compensate for a lack of technical ability at the beginning with strength.

“When you start climbing, it’s super rewarding to see that rapid progress, because your body is pretty quick to adapt to it,” says Livesey. Such adaptability is the result of the intense nature of the workout, similar to HIIT, which gets you really fit really quickly. Of course, to continue to succeed, fitness must eventually be matched by technique, and that’s what slows your progress at the intermediate levels. Good technique, it turns out, is as difficult to acquire as muscle, if not more so. “When you’re a V7 climber trying to progress up to a V8, it’s a lot of hard work,” Livesey says.

But you can make that work a lot easier by improving your strength and flexibility. Chiefly with pullups, of course, but also with workouts like yoga, which, thanks to its emphasis on flexibility, core strength, and body-weight exercises, can dramatically improve your abilities. One thing that surprises a lot of beginners is how much you use your legs in climbing. Think about it this way: You wouldn’t pull yourself up a ladder using only your arms. It’s the same with climbing.

Also important to keep in mind if you start climbing is muscle balance. Since climbing is all about pulling, you want your exercises in the weight room to involve pushing, especially with regard to your chest and triceps.

But if all you’re doing is climbing, expect to gain strength fairly quickly. Muscle gains require variety, of course, and nothing confuses your muscles like rock climbing. “One of the big differences with rock climbing is the variety of movement you’re performing,” says Livesey. “Your body doesn’t adapt to it as it does with more regimented exercises. So you keep getting stronger.” Most rock-climbing gyms will change the routes every four to six weeks as well, so your body never even has a chance to get in a rut. And as for the workout itself, besides the obvious muscle groups of arms and back, it also works your legs and, to a fairly aggressive extent, your core. Frankly, I’ve seen more six-packs in rock-climbing gyms than in any other workout space I’ve ever been to. And though climbing rewards a good strength-to-weight ratio, anyone can climb. One of the most elite climbers of the 1980s, in fact, was John Dunne, a Brit known as much for his 200-pound frame as for his crazy skills.

Best of all, climbing is mentally engrossing. “I know from personal experience, when people go to a conventional gym, they’re clock watching,” says Livesey. “With climbing, you almost have the opposite problem, where you’ve been climbing for two or three hours and suddenly realize you should have been out of there 40 minutes ago.” (I can attest to this: I became so engrossed in that one V3 that I blew right past an 8 o’clock dinner appointment.) This is due to the problem-solving aspects of climbing. Routes are literally called “problems,” and when you finish a climb, you “send” it. The mental focus required to send the problem puts you in a zone where you lose track of everything else that’s going on around you. Imagine powering through a CrossFit or SoulCycle workout while at the same time working through a complicated Sudoku puzzle, and you have some understanding of what rock climbing is.

As corny as it sounds, climbing is also communal.

“We’re all about getting people to take their headphones out,” says Stewart. The act of climbing itself requires a tremendous burst of physical exertion, which means that most of what you’re actually doing while you’re at the gym is resting. “While you’re resting your body to be able to succeed, you can talk to the people around you,” says Jeremy Balboni. Mikhail Martin, a coder and a regular at Brooklyn Boulders, says he often goes in just to hang out with other climbers, even when he doesn’t feel like climbing. “I’ll go anyway and just have a good time. And those are the days when I end up climbing my best.”

And, it’s worth mentioning, rock climbing attracts an inordinate number of women. Fit women. Like Sierra Blair-Coyle, who is an occasional model and, more important, a two-time national champion rock climber. Actress Lea Michelle apparently loves climbing so much she once conducted a magazine interview at a climbing gym. “I think we can take credit for at least two marriages right now,” says Stewart, who notes that it’s much easier to strike up a conversation with a woman while climbing than on the treadmill. Just don’t give her a lecture. “One thing that drives me crazy is when guys try to mansplain how to climb to women,” says Cyrena Lee. You’ll not only look like an asshole, but it’s likely that you’ll be giving “advice” to someone who’s better than you.

As I rest for the last time on the padded floor in front of my yellow V3, I can’t help but stare at the girl burning up the V9 next to me. She’s so clearly focused on the problem in front of her, so in control, so determined, that I wouldn’t dream of trying to talk to her—well, at least not now. That’s when I’m reminded of a conversation I had earlier in the afternoon with Balboni. “It’s easy to bond here around this single purpose,” he told me, his hand patting the wall, “which is succeeding at something that’s really hard.”

So maybe I’ll strike up a conversation with her afterward, whether it’s by the gym’s café or near a water station. After all, I’ve fallen on my face for the past two hours. I could use some expert advice.