Thousands of people came out overnight and in the middle of the day to catch it.
"It's like a collective cultural experience you can't help but be a part of," said Avenger's fan Meghan McDermott.
She's right. And it has other fans geared up to go.
"I'm nervous, I'm excited, been waiting for this for months," said moviegoer Holly Good.
But if you really want to know why superheroes are so beloved, talk to an expert. ABC7 spoke to veteran comic book creator Jill Thompson, who teaches storytelling at the International School of Comics in Chicago and asked her, why do we love superheroes so much?
"Superheroes are our modern mythology," Thompson said. "We've got heroes fighting evil, they're giving us life lessons, and they're always teaching us about ourselves...they make you feel good."
Those leaving the theaters Friday said to be ready for all the feels.
"I know that every human emotion that could possibly happen I will live through in the next three hours, so I'm excited," Avengers fan Alexis Littman said.
"You kind of get this sense of a reminder why you're in it to begin with and why you love it, and why you'll probably end up sticking with it for more years to come," said fan James Tschirhart as he left the theater.
You can learn more about comic book creator Jill Thompson and the International School of Comics at http://www.schoolofcomics.us/ and https://www.thescarygodmother.com/
SUPERFANS ATTEND OVERNIGHT SHOWINGS
Whether they couldn't grab coveted Thursday early screening tickets before record-breaking sellouts, or they preferred a very early start to their day, Avengers superhero superfans shuffled through AMC River East 21 in Streeterville overnight Thursday into Friday to be among the first movie-goers to watch "Avengers: Endgame."
"I had to see it," said Lorena Maldonado after finishing the movie just in time to make it to work for 7 a.m.
Another middle-of-the-night viewer Albert Egbo said his roughly 3 a.m. showing start time had fewer than a dozen people seated, making for "awkward, intimate vibes."
But he brushed that aside.
"It was perfect, man. There's literally nothing I could add to that movie... it was that good," Egbo added.
As the sun rose Friday morning, there was something of a shift change at the theater. Fans walked out of the theaters as more were heading in; the concession stand stops included popcorn with more coffees ordered than you'd expect at the movies.
"I can't imagine that many people being here today and then it's perfect because right after this I go to work," remarked Christopher Wartman with a cup in-hand.
Some people appeared to have nothing else on their schedules, including David Abarca who pre-ordered tickets to three showings running Thursday into Friday.
He said with a 21-movie build up to this "Endgame" finale, he had a feeling it would be awesome.
"Worth it all three times," he said after that third screening.
What's so enticing about this conclusion to the Avengers' saga? We don't know because we made sure fans didn't share any spoilers.
But here's a hint: "Some characters it seems like they might have wrapped up nicely and other characters it seems like they gave room to grow into something bigger or room to give someone else an opportunity to grow into something bigger," Egbo said.
There are plenty of showings of "Avengers: Endgame" at AMC in River East this weekend for those eager to watch. In fact, this is one of 17 AMC theaters to be open for 72 hours straight this weekend to kick off this historic movie event in high gear.
ABC 7 and Marvel Studios are owned by The Walt Disney Company.