“This is it,” Paul Abugattas said Sunday afternoon, as fireworks blasted off and full cups of beers flew through the air and D.C. United kicked off its last-ever game at RFK Stadium. Then he hugged a nearby friend, a 49-year-old Washington native who had flown home from Colorado to say goodbye to the city’s most beloved pile of concrete.

Washington has bid farewell to RFK Stadium before, on other days overflowing with other emotions. There was anger in 1971, when the Senators’ final game before skipping town was cut one out short by fans running rampant on the field. There was nostalgia in 1996, when Redskins fans overwhelmed security at the team’s final game in the District, pouring onto the field to dig up pieces of turf as souvenirs. There was excitement in 2007, when the Nationals moved across town to their shiny new home, leaving United behind.

The emotions on this afternoon felt mostly like love — for a place as anachronistic in modern sports as black-and-white newsreels or foam fingers, score hotlines or 10-cent hog dogs. Nothing about the 56-year-old stadium fits in 2017; not the architecture, not the dark and reeking concourses, not the peeling paint, not the amenities that would embarrass a minor league baseball team. And yet more than 41,000 people — soccer lifers, D.C. sports fans and hardcore United supporters — pumped the joint full of electricity, and love, at least one last time.

“It’s a broken-down dirty old dump, but it’s our broken-down dirty old dump,” said longtime United fan Brad Clements, words repeated over and over throughout the afternoon, often with some homey profanities mixed in.

Like me, Clements had climbed into the stadium’s especially decrepit upper deck during the first half of United’s season-ending 2-1 loss to the New York Red Bulls, just to wander around and soak in the view. Behind him was that unforgettable look toward the city’s core: the broad expanse of East Capitol Street, the Capitol dome, the Washington Monument. That vista is so different from those offered at Nationals Park and Capital One Arena, which are tucked into tighter quarters and almost sneak up on you. Don’t even mention FedEx Field, that alien spaceship plopped down among gas stations and fast-food chains.

But RFK was pasted into the city’s design, a place you pointed out to relatives from the top of the National Cathedral, a place that beckoned as you biked east from Capitol Hill or drove west from Maryland or followed the crowds from the nearby Metro station. You saw the familiar swooping profile looming in front of you, and you felt like you were heading someplace important, to a building that mattered.

“From day one — Oct. 7, 1961 — D.C. Stadium [as it was then called] was centered in this city’s scheme of things as sports stadiums elsewhere seldom are,” the great critic Benjamin Forgey wrote, a quarter-century ago this week. “The stadium, despite its rather anonymous architectural image, did and does say ‘Washington’ in a unique way.”

United’s fans inherited that uniqueness after the Redskins bolted for Maryland — and then they hopped it up with smoke bombs and sweat and soul. Perched in the highest reaches of the stadium, Clements wasn’t the only one taking in the bouncing stands and the supporters who had helped turn this generic multi-use stadium into a temple of American soccer.

“It’s a throwback. All the new stadiums — like Yankee Stadium — they feel like a mall,” said 28-year old Mark Cunningham, a Washington sports fan who came by himself to this, his first United game, sitting alone in the very top row. As he talked, the crowd howled; “Doesn’t the noise feel different?” Cunningham asked. “That roar? I don’t know. It’s pretty pure.”

Purity in putrefaction, maybe, but he’s not wrong. There was an official program of events on Sunday, with an alumni game and a postgame ceremony and 90 minutes of Major League Soccer in between. But, as with so many other afternoons at RFK Stadium, it often felt like the fans were in charge of the agenda. They orchestrated the cheers. They took over the concourse at halftime with a raucous, ear-piercing drum circle, happy chaos created together by old men and shirtless 20-somethings and kids on parents’ shoulders. (“A little hectic, but a lot of fun,” said 13-year-old Nellie Hartell, when she emerged with her father from the pulsating mob.)

They waved flags, clapped to and beyond the final whistle. Then some of them stomped on those classic orange seats until they splintered, looking for a souvenir. There was something ad hoc about it all, something populist. Somehow, the adults in suits had allowed the people control over this one last venue.

“The inmates kind of ran the asylum here for two decades,” said Paul Sotoudeh, a longtime leader of the Screaming Eagles, one of the largest supporters groups. “The myth of RFK, the legend of RFK — we got to create that on our own.”

“Places like this, the only thing going on is the game,” said James Lambert, another Screaming Eagles leader. “There aren’t many stadiums left where the game is the event.”

“It ignores any appearance of corporate professionalism,” added Alex Harkavy, as fans in front of him deployed red-tinted smoke and chanted profanities about the visiting Red Bulls. “It stood the test of time as a lesson in pure functionality. You’re always going to have fun here, and there aren’t stadiums meant to do that anymore.”

And so fans met boyfriends and girlfriends and husbands and wives here; “This was the old MySpace,” said one, who found two different boyfriends at this stadium. They got drunk in the infamous Lot 8 as 20-somethings, and then grew up and brought their kids here as 30- and 40-somethings. Some went from childhood to adulthood in the building, like Carlos Castellon, who was 7 when he attended MLS Cup in 1997, “and I’ve been here ever since,” he said. Others — like United Coach Ben Olsen — spent the prime of their lives roaming the place’s ridiculous catwalks or tunnels or green centerpiece; “20 years of my life was spent on this field,” Olsen told the crowd after the game.

“It’s a community,” as United legend John Harkes put it, using a word so many others had hinted at all afternoon. “It’s gritty. It’s real. It’s authentic. And we love it.”

It’s also well past its prime, easier to mourn when something better awaits. Some supporters are nervous about whether they’ll be as central to the game-day experience at the new, corporate-branded stadium at Buzzard Point. Others can’t wait to inhabit a place that doesn’t smell, a place that will take United out of its decaying time warp and into modernity.

And there will still be more events at RFK, as the city tries to figure out how best to use the valuable site. That means at least one more goodbye — in the form of a wrecking ball — and more retrospectives, and more memories. But it’s hard to imagine a more loving goodbye than the one the old pile of concrete received on this night.

“Look at it,” said Srdan Bastaic, another longtime supporter, shirtless and spent after hours of screaming, as he scanned the emptying building. “I don’t know, man. It’s beautiful, isn’t it?”

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