“It’s 6 o’clock! Lower that screen!”

A thunderclap of shouts rolls in approval. The crowd at New York’s AMC Empire 25 is getting restless, but it would be unfair to call them impatient. After 11 consecutive Marvel movies, they’re ready to cap off a 31-hour marathon with a conclusion they’ve all been waiting for: Avengers: Infinity War. Just off of Times Square, dozens of fans, prepared with blankets, pillows, snacks, and caffeine, have committed to celebrating the long-anticipated release of Marvel’s latest film with a special marathon event.

Though the marathon began just a day before, the start of the kickoff movie, Iron Man, feels like it was a fever dream. As the lights dim one final time, one fan excitedly tells a friend, “I’ve been waiting for this for 10 years.”

That’s not an exaggeration. Infinity War unites characters and ties together plotlines from more than a decade of Marvel movies, from Iron Man to this winter’s Thor: Ragnarok and Black Panther. It’s been nearly a decade to the day since the premiere of Iron Man in 2008, the official start of this long and winding journey. To celebrate, a handful of theaters across America are hosting these marathons, and some fans have traveled from nearby cities to be here. “I got a few hours of sleep on the train, and I’m hoping to get a few shut-eye moments between films, but I’m going to try and stay awake for the entire thing,” says fan Tony Ferrandino, who has come alone, with a healthy supply of fluids in tow. Hydration is the key to surviving the marathon, he says. “It’s a test of endurance.”

The marathon is an event for fans, but in many ways, it is also a trial to overcome. For 31 hours, that theater would become our home — one with no showers and only cramped spaces to rest our bodies. If you want to sleep, you nod off in your chair, or stake out a minimal amount of real estate on the theater floor.

For the first few movies, the marathon feels easy to sink into. It’s a rainy Wednesday afternoon fading into night, and we’re all warm inside, shoveling popcorn into our maws and watching beautiful people punch stuff. There’s already an antique quality to some of these films, whether it’s Robert Downey Jr.’s Tony Stark cracking a joke about MySpace, or remembering a time when bony Edward Norton played the Hulk. Marvel’s films have evolved, just as surely as the series’ wigs have. What began as typical superhero fare has become the standard for feel-good action movies. As each new film ladles on even more references to other branches of its story, it’s easy to feel more and more like you’re in on the joke.

“I wanted to experience it,” says Keith Walker, a lifelong comics reader and devotee of the MCU films. “Ten years ago, you saw [Iron Man] with a group of strangers. Perhaps you knew it was something special then. But now, it’s just [become] an epic event.” His marathon companion, Rory Hearn, is of the same mind. “You’ve got to look at it as an endeavor,” he says, likening the marathon to a camping trip. “It’s not just a trip to the movies.” Walker is new to marathoning, while Hearn is an old hand; he also attended the 29-hour Avengers: Age of Ultron marathon in 2015. At this point, we’re three films into the marathon, and this has become a helpful mindset to adopt. I’ve packed some basic toiletries, like toothpaste and deodorant (which I’ll use liberally throughout the next 24 hours), but Walker has me beat. “I brought toilet paper, because I’m not going to wipe my ass with that shitty-ass [theater] toilet paper,” he says.

“I brought toilet paper.”

“[Red Bull] is essential,” says Frances Illa, another pro marathoner sitting nearby. She attended the 2015 Age of Ultron marathon with a friend, and recommends naps (“you’ll go insane”) and avoiding other junk food, but the caffeine is necessary. “You have to do it in the middle of the second-to-last movie so you are completely hyped up.”

The crowd is an excitable one. They cheer at every swelling, heroic moment, laugh and hoot at a good reference or in-joke, and clap when each film ends. Their excitement is infectious and endearing — a crowd of people so thrilled to be seeing a couple of their favorite movies with a group of people just like them.

One fan praises Captain America actor Chris Evans as a real-life hero decrying Nazis and hate on Twitter, while another adjusts their Spider-Man pajamas. As Illa put it to me earlier, it’s the audience that makes the marathon really unique. “When you see it individually, you always have an enthusiastic audience, and it’s fun,” she said. “But each audience is different. When you’re in a marathon like this, you’re with literally a large group of like-minded people. We’re all geeking out about it. We all love the movies so much. We all love Marvel. It’s just fun, the vibe is always good, you meet really great people. We’re all just one big group of people that love these movies. One big nerdy family.”

But sitting and staring at a screen for that long — no matter how feel-good the action is — can make anyone start to feel like they’re losing their mind. If you wander outside the theater, the bright lights of Times Square make it seem as though night never came. Time is now measured in movies. The exhaustion and ache to find a downy pillow hits around 2AM, when the novelty and our deodorant has worn off, and people are succumbing to sleep. While an unknown number of people snore in their chairs, a handful have gone a step further, setting up blanket forts near outlets as they charge their phones. Some wander off to empty theaters to sleep in recliner chairs. We are the only people in the building, and we’ve taken over without hesitation.

Guardians of the Galaxy rolls past, followed by Age of Ultron at 4:30AM. These have become the two most popular films to sleep through — either because people have seen the first too often, or they don’t much care for the second. The natural urge to be asleep doesn’t hurt, either. As proper morning hours creep in, the theater gets a little livelier. People run out for breakfast during the next break between movies, just shy of an hour. We’ve crossed the halfway mark and are churning ahead to the end. The theater has become a wasteland of scattered popcorn and trash, the air warm and thick with the smell of bodies.

It’s the sort of loyalty a company would kill for

Eventually, inevitably, we arrive at the last break. Black Panther has finished, and in just an hour, Infinity War will begin at 6, an hour earlier than the film’s other screenings. It’s our treat for our endurance, and the energy of the crowd has returned. People run around in their hero-adorned hoodies and shirts, yelling and clapping as they discuss their hopes and fears for the movie. Catching up with Walker and Hearn, I find them still energetic and engaged.

“I’m worried, not gonna lie,” he says. “I have no idea what I’m about to watch. I have no idea what cataclysmic event is about to happen. I’m excited, yet also just trying to keep my expectations low.” Hearn is feeling more confident. “I have full faith in Marvel after 10 years of excellent movies. I think this is going to be amazing,” he says. “I have a new rush of adrenaline now that we finally got through all the other movies, and it’s coming to Infinity War. I can feel the tiredness setting in, but in the same sense, the adrenaline is like, ‘Yes, this is what I’ve been waiting for.’”

I do one last lap around the theater and choke down a Red Bull. Across the street at the Regal, fans in costume have started lining up for their showing of Infinity War. My eyes are burning from strain, and I’m dying to eat something green. Back inside, people have begun to settle in. In the last 10 minutes, they’re more rambunctious than ever, yelling and clapping and swapping theories with friends. Clif Wilmer, who came in from DC just to attend this marathon, echoes my thoughts on the entire experience: it’s sheer absurdity. But in his eyes, that’s what makes it so appealing. “Movies for me have become kind of a treat because of my work schedule,” Wilmer says. “My first vacation in three years is doing this. I came to a city I basically am not a fan of to sit in a theater and pull an all-nighter with a bunch of strangers.”

It’s the sort of loyalty a company would kill for. But it isn’t just Marvel’s decade spent building a devoted fanbase for the MCU. It has created a rare cinema event that can’t currently be matched by any other franchise on film. There is no other movie series out there that can match the sheer star power of Marvel, let alone how many individual stories it’s woven together as one cohesive universe. Infinity War isn’t just another Avengers movie. It’s the embodiment of their Hollywood legacy.

For more than two and a half hours, fans watch as Infinity War unfolds onscreen. It’s the culmination of a decade’s worth of films that have laid a groundbreaking number of narrative threads, Easter eggs, and jokes across one universe. They cheer at the appearance of each new hero and clap for the one-liners; they gasp and cry out when things go wrong for their favorite heroes. It’s a roller coaster of excitement and emotion. The film ends with thunderous applause, but as the credits roll, people remain focused on the screen. They’re waiting for a final treat: a post-credits scene that may or may not exist — one last taste before they say goodbye.