Captain America: Civil War is great for a number of reasons—character development and growth, the grounded story, Black Panther—but the best sequence happens about a third of the way through when the two sides (Team Iron Man and Team Captain America) clash at a German airport. It’s 17 minutes of pure superhero bliss and among the most entertaining sequences in Hollywood history.

Turns out, it was almost entirely digital.

Note there are minor spoilers ahead.

Marvel has already shared behind-the-scenes footage of how parts of the airport fight was filmed, but we didn’t realize how much of it was CGI. Did you notice? I sure didn’t, and I think that’s a major testament to the small miracle performed by Industrial Light & Magic.

In an interview with The Verge, ILM visual effects supervisor Russell Earl revealed the astonishing amount of work that went into creating the airport fight, which featured explosions, magic, flying, and a dozen different characters on screen at once.

“Spider-Man, Giant-Man, and Black Panther are always one-hundred percent CGI,” Earl explained. “Iron Man, War Machine, and then we’ve got Vision.”

Meanwhile, CGI wasn’t necessary to create characters such as Black Widow, Captain America, and Winter Soldier because they remained more grounded during the fight and don’t necessarily have any powers. According to The Verge, basically any character not wearing a mask wasn’t made of 100-percent CGI. What’s even crazier is that some of the characters shot their live-action sequences in Atlanta, rather than at an airport in Germany, which is where some of the principal cast members shot their scenes.

The Verge’s reports reveals a few other neat details, such as how ILM worked to make Spider-Man and Black Panther look as realistic as possible. Marvel actually intended on having actors inside of suits on camera, but they decided to go entirely CGI because it allowed the filmmakers achieve the exact vision they were going for.

Over the past few years, CGI has gotten a bad rap for becoming the bane of Hollywood, but when utilized correctly—like in Deadpool’s freeway sequence—it gives filmmakers more flexibility to entertain audiences. And if nobody is the wiser CGI was used, they’ve done their job.

Check out the full report below.