Normally, the relaxed fingering of an electric guitar wouldn’t have seemed strange music for Barcelona. During my week-long stay, I had already heard a severely pierced rapper rhyme to the beat of a plastic kazoo and a shoeless saxophonist in a powder-blue suit playing a half-speed rendition of “Blowin’ in the Wind.” But that was on La Rambla, the busker-friendly pedestrian throughway in the heart of the old city. I was spending the afternoon on Montjuic, Barcelona’s hilly and quiet patch of green which, during the 1992 Summer Olympics, had hosted several events. Up there, far away from the bustle, the faint, amplified waves startled me.

While they appeared to come from all directions at first, the licks grew louder as I walked along. Then, suddenly, a powerful rhythm section kicked in. Each beat of the snare drum snapped through my body; these were no stray buskers. I checked my map and pinpointed the origin of the sound: Palau Sant Jordi, where the U.S. basketball Dream Team had captured its gold medal. Soon a sax player joined the mix and a familiar tune rattled the air. I recognized the song, yet I couldn’t place the artist or the title. Before my brain could process what was happening, it was scooped by an unmistakably hearty American growl: Bruce Springsteen.

I broke off my intended route and, moving double-time, followed his voice to the side of the arena. Men in orange safety vests were moving heavy objects in and out of the arena with forklifts through a giant service entrance. The Springsteen classic “Prove It All Night” soared through the opening unimpeded. Either it was Springsteen or one hell of a cover band. I fell into place with a half-dozen other people atop a small, grassy hill. We stood 50 yards from the door, restricted from further access by a chain-link fence. I closed my eyes and listened. It sounded as good as any outdoor concert I’ve ever attended, maybe better.

“This is nice,” I mumbled to nobody in particular.

A man stood with his face pressed against the fence. He turned around.

“This is very nice,” he said. He smiled.

His name was Doug and he wore a T-shirt with the words “Battlefield Orchards, Freehold, NJ,” printed across the front. Doug knew precisely why Bruce Springsteen and the E-Street Band were performing in an empty arena in Barcelona at 2 p.m. on a Thursday. He had come to Barcelona specifically for the first concert of the group’s reunion tour, which was scheduled for the following night. Today, he said, was the final rehearsal. We had just gotten lucky by stumbling upon a big open door. My timing, he added, was impeccable. Clarence, Roy, Max, Nils, Garry and the rest of the band had pulled in much earlier—but Bruce had just arrived 15 minutes ago. Doug turned away for a moment, moving his arms and one foot frantically in coordination with the drumbeat.

In the span of a drum fill, Doug and I bonded like brothers. I made fast friends with the others, too: Netherlands Dick, who, like Doug, referred to the band members only by their first names, and wondered aloud about things like whether Roy was playing the grand piano or the synthesizer; and Javier, a skinny man in a baseball cap, who speculated about when people would line up to get into the show the next night.

Doug, however, was our point man. He seemed to know everything from song titles to the names of the band members’ pets, and he told us the story of a rehearsal in New Jersey a few weeks earlier. Several fans, he said, had waited outside for hours on a cold, bitter day. Toward the end of the rehearsal, a security guard approached them and announced that it was their lucky day. He escorted them inside, where they were treated to a five-song set. Bruce even took requests.

As the band fired up “Two Hearts,” I found a comfortable spot on the grass, peeled an orange and settled in, hoping for a repeat of the New Jersey story. Javier wandered off, returning minutes later during “Darkness on the Edge of Town” with a message: It sounds better in the plaza at the front of the arena. We packed up and sped around the corner to the plaza where, indeed, several doors were flung open and the sound was strong and clear. Doug said he hoped it sounded so good on opening night.

But that wasn’t the best part. Dozens more people—both hard-core fans and unknowing wanderers like me—had discovered the gig, and they were having an impromptu party. People danced with strangers and sang along with Springsteen. Young girls dressed in black sat cross-legged and smoked Marlboros. Grizzled men in shabby denim and dirty baseball caps silently bobbed their heads. Mountain bikers in bright Lycra straddled their machines and listened. Those with cellular phones called friends. At one point, two couples plopped down with a few boxes of deep-dish pizza.

Inside, our exclusive party band played on: “Youngstown,” “Murder, Inc.,” “Badlands.” Occasionally someone would arrive on the scene, pause in recognition, then yell, “Brooooooce!” Others pledged their allegiance to the sax player, Clarence Clemons, with shouts of “Beeeeeeg Man!”

As the rehearsal progressed, the story of the freezing but fortunate New Jersey fans rippled through the crowd. It’s doubtful we’ll get in for a private audience, I thought, as I shed a layer of clothing, reapplied sunscreen to my face and reveled as a haunting version of my favorite Springsteen song, ”The River,” wafted into the plaza. Still, I hoped.

More than two hours in, the band revved up a lengthy “10th Avenue Freeze-Out.” Amy and Patty, two Chicagoans just on the scene, looked at each other with their mouths wide open. A famous rock critic from a big-city paper dropped in, too, comparing notes with Doug on times and set lists. And Doug, whenever inspiration struck, jumped back on the air drums. Netherlands Dick, who had seen several Springsteen concerts in Europe over the years, wandered around in rapture. We started talking.

“After every tour I say it’s over,” he said of his enchantment with Springsteen. “Then I’m sitting here and I hear him and it catches me.” He stopped and raised his hand to his face. “I almost start to cry.”

I wasn’t prepared for such an emotional reaction. Yet as I looked around the plaza, his overwhelming happiness didn’t seem nutty or unwarranted. We had Springsteen all to ourselves. We had uncommon camaraderie among complete strangers. We had deep-dish pizza. Something special was happening. I chalked it up to the power of music and beautiful serendipity, the greatest joy of traveling. Dick, I guess, attributed it all to Springsteen.

Eventually, Patty, Amy and the critic joined the rest of us in a circle on the ground. We talked about chord progressions and Elliott Smith records, Charles Barkley and hometowns. And we listened as the band performed hit after hit: “Lucky Town,” “The Promised Land,” “She’s the One.” True to legend, the band was playing forever. Then, during “Bobby Jean,” a security guard on a motorcycle pulled up beside us. I couldn’t remember whether Doug had mentioned anything about a motorcycle in the New Jersey story. Still, I hoped.

“Son las seis,” he said. “Tienen que salir.”

It was 6 p.m. and we were being ordered to leave the plaza. This was a setback, for sure, but we wouldn’t be denied our encore. We boomeranged to the hill near the service entrance. Springsteen’s scream of “One, two, three, four,” signaling the beginning of the end of “Born to Run,” easily pierced the now-closed door. Doug’s timing on the air drums remained impeccable. After “Thunder Road,” “If I Should Fall Behind” and “Land of Hope and Dreams,” the music stopped. But we remained. After four hours listening blindly, we wanted to actually see Springsteen. And, in equal measure, we wanted him to see us.

Clemons walked out first. We cheered. He smiled and waved. Consensus among the crowd was that the Big Man is, in fact, very big. Soon after, the rest of the band filed out. We cheered again. They smiled and waved, then boarded a mini-bus and drove away. Minutes later, Springsteen emerged wearing sunglasses, a beret and a leather jacket. A bottle of water peeked out of one pocket. In an instant it was Idlewild, 1964, the day the Beatles arrived in America. Women screamed high-pitched screams and men yelled their hero’s name. We applauded wildly.

Springsteen’s next decision thrilled everyone except me and his bodyguard: He started running up the hill toward us. The crowd devolved into a giddy mob, collapsing against the fence. Not prepared for the rush, I was swept into the chain-link. My sunglasses tweaked against the metal and twisted off my nose. As I braced myself to remain upright, others began climbing the fence. Springsteen’s burly sideman shooed them away as best he could and yelled vague instructions to his client. “Watch it, Boss, watch it.”

But Springsteen, undoubtedly a veteran of giddy mobs in many nations, was unflappable. He shook hands through the fence, asked where a few people were from and thanked us for being there. Calm prevailed. Then, as quickly as he came up, Springsteen descended the hill, hopped into a vehicle and fled. The party was officially over.

I said goodbyes to my new friends. Doug offered to sell me one of his spare tickets for opening night. I was booked for the sleeper train out of town, however, and politely declined. I gave him my e-mail address, though, and asked him to fill me in about the show when he got a chance.

Days later, I received a missive: “Oh my GOD!!! You should have seen it/me on the floor among the masses. I was standing dead center, directly in front of Bruce’s mic., approx. 30 feet from the stage. I was literally covered in sweat, occasionally short on breath, and quite sure that at that moment, there was nowhere else on earth I’d rather be.”

I smiled, thinking back to my own experience with Bruce, Clarence, Max and the rest of the band. I knew exactly how he felt.

Michael Yessis is the co-editor of World Hum.