Ahead of the July 2, 1996 release of Independence Day, trailers and television commercials emphasized the disaster movie’s massive alien ships, explosions and other spectacular visuals above all other elements. Why? To put as many warm bodies in theater seats as possible. The marketing magic worked, because director Roland Emmerich and writer/producer Dean Devlin’s action epic grossed over $817 million at the global box office on a $75 million budget. Besides, it involved Will Smith whoopin’ E.T.’s ass. Who wouldn’t pay to see that? After most of the explosions of the movie’s opening passed, however, a funny thing happened in the second act.

Aboard Air Force One, several governmental and civilian characters argue about what the next step should be. Julius Levinson (Judd Hirsch) mentions Area 51, the famous and secretive military installation located outside of Las Vegas, Nevada. You know, that place where they supposedly took the remains of a supposed UFO crash near Roswell, New Mexico in 1947. President Whitmore (Bill Pullman) assures Julius no such place exists, but the Secretary of Defense corrects this false assumption. Area 51 (as a repository of alien goodies) does exist in Independence Day‘s alternate history, and its existence sends the story into an entirely new direction.

It’s a direction that Emmerich and Devlin badly wanted to go, but the United States military wasn’t happy about it. In fact, their entertainment liaisons — who’d originally agreed to supply Independence Day with costumes and props — threatened to pull the armed forces’ support if all references to the base weren’t excised from the script. It’s one of the most famous bits of behind-the-scenes trivia from the production, which Devlin confirms in his DVD commentary track with Emmerich:

In fact, the United States military was going to support this and supply us with a lot of costumes and airplanes and stuff. Their one demand was that we remove Area 51 from the film, and we didn’t want to do that. So they withdrew their support.

Devlin doesn’t go into any specific detail, but he didn’t have to. It’s clear from his admission that, because of the story’s heavy reliance on Area 51, the production’s military-provided and approved advisers decided not to participate. Much of this had to do with the story’s semi-realistic use of the United States Air Force, especially through the lens of Pullman’s fighter pilot-turned-President, and Smith’s Captain Steve Hiller.

It also had to do with the second act’s infusion of Area 51 — both the actual base, and the mythos surrounding it — which filled the rest of the movie with shout outs to the nation’s (and the world’s) aerial might. Sure, maybe this was inspired by what the U.S. government considers a gross exaggeration of the truth, but Independence Day is a work of fiction after all. (Unless you’re partial to X-Files-like conspiracy theories.) As Emmerich notes in the commentary track, science fiction like this works well when injected with a heavy dose of modern mythology:

This is probably one of one of the biggest twists of the movie. In the middle of the movie, all of a sudden, you come up with Area 51. There’s this mythology about this place where they keep spaceships. For Dean and I, it was the most important part because it ties together this mythology that people believe in to the movie. So it feels more real.

Throwing the Area 51 twist into the middle of the film amplifies its heavier sci-fi elements, but it also grounds its more realistic qualities. That’s not so much because Area 51 having a Raiders of the Lost Ark-like storage facility for secret stuff was more realistic, per se, but because its presence in modern American pop culture is something with which many viewers were familiar. Whether theatergoers had seen it on The X-Files, the gimmicky Alien Autopsy: Fact or Fiction special from the previous summer, or other films and shows, the public knew just enough to recall what all the Roswell hoopla in ’47 was about.

As a result, the hidden military installation gave Emmerich and Devlin just the punch they needed to pivot Independence Day toward its third act and, by the grace of Brent Spiner’s non-death as Dr. Okun, help the humans win their three-day war against the alien invaders.

Meanwhile, Independence Day: Resurgence invades theaters on June 24. Until then, here’s a clip…