In the summer of 1996, “Macarena” was on its way to becoming the year’s number one pop hit, The Fresh Prince of Bel-Air had just wrapped its six-season run, and that show’s star, Will Smith, was just kicking off a period in his career that would see him star in one major film per year for the next dozen years. When Independence Day hit theaters on July 3, it quickly established itself as the year’s biggest film (easily trouncing Twister, Mission: Impossible, and The Rock in ticket sales), and rocketed Smith into the outer stratosphere of fame.

In its 20 years on Earth, you might’ve learned a lot about Roland Emmerich’s sci-fi blockbuster, but plenty of the film’s biggest secrets have remained hidden. Here are just a handful of Independence Day facts—rescued from Hollywood’s most top-secret underground bunkers—that might make you see this extraterrestrial classic in a whole new beam of light.

1. MANY SCENES WERE SHOT AT WENDOVER AIRFIELD, EX-HOME OF THE ENOLA GAY.

Independence Day features a number of scenes filmed at Utah’s historic Wendover Airfield, including exterior shots of “Area 51,” various moments of heroism and terror for the film’s fighter pilots, and President Thomas J. Whitmore’s (Bill Pullman’s) landmark pre-battle speech. The base has played host to numerous films and military projects over the years, and once housed the B-29 bomber Enola Gay, which became the first aircraft to drop an atomic bomb.

2. THE FILM LOST ITS MILITARY SUPPORT DUE TO ITS AREA 51 REFERENCES.

In its roundup of insights from the Independence Day DVD commentary, Film School Rejects points out that the U.S. military had initially agreed to support the film’s production by offering greater access to military facilities and consultation from real-life officers, soldiers, and pilots. However, according to the film’s producer and co-writer Dean Devlin, the military withdrew its support after learning about the script’s multiple references to Area 51 being a hub for extraterrestrial projects.

3. CALIFORNIANS THOUGHT THE “WELCOME WAGON” HELICOPTER WAS A REAL UFO.

When the production team tested out the light-rigged helicopter that would represent humankind’s “Welcome Wagon” for alien visitors, more than 150 Californians called the police to report UFO sightings.

4. THE FILM’S EL TORO AIRBASE IS A NOD TO THE WAR OF THE WORLDS.

Independence Day takes many cues from the 1953 sci-fi flick, an adaptation of H. G. Wells’ classic 1898 novel, which similarly sees aliens attack the planet and resist our heaviest weapons. In Emmerich’s film, Will Smith’s squadron of fighter pilots is stationed at Marine Corps Air Station El Toro, a real-life California facility that was decommissioned in 1999. The site was also home base for the atomic bomber that tries (and fails) to destroy invading Martians in The War of the Worlds.

5. THE COMPUTER VIRUS THAT SAVES THE DAY IS ALSO A REFERENCE TO THE WAR OF THE WORLDS.

In both the novel and film versions of The War of the Worlds, mankind’s biggest guns fail to take down Martian attackers. Instead, it’s tiny viruses in our atmosphere—mostly harmless to humans, but foreign to Martian immune systems—that finally do the job. In Independence Day, too, Bill Pullman’s presidential order to “nuke the bastards” doesn’t even make a dent in the aliens’ front, but a cunning (if confusing) computer virus manages to destroy the invaders at last.

In the case of Independence Day’s viral “Hail Mary,” fans have raised criticism—and plenty of eyebrows—over the years regarding just how on Earth David Levinson (played by Jeff Goldblum) could have drummed up a computer virus that affects alien technology so quickly. Devlin offered some answers during a 2014 Reddit AMA:

"Okay: what Jeff Goldblum’s character discovered was that the programming structure of the alien ship was a binary code. And as any beginning programmer can tell you, binary code is a series of ones and zeroes. What Goldblum’s character did was turn the ones into zeroes and the zeroes into ones, effectively reversing the code that was sent."

Cracked notes that there was also a seven-minute scene that would’ve addressed this issue for viewers from the very beginning, and which suggests that modern computers in the Independence Day universe are descended from a reverse-engineered version of recovered alien tech courtesy Area 51. Unfortunately, that scene was cut from the final release of the film, only adding to viewers’ confusion.

6. THE ALIENS’ FOUL SLIME WAS REALLY K-Y JELLY.

As the New York Daily News reported in 1996, the very alien-seeming goo that slicked the surfaces of some Independence Day invaders was actually personal lubricant.

7. ITS “DEEP SPACE SATELLITE DEVLIN” REFERENCES STAR WARS.

Detail-oriented fans may have noticed that the “Deep Space Satellite Devlin” (named for the film’s producer and co-writer) that shows up on a Search for Extraterrestrial Intelligence (SETI) institute computer monitor looks eerily familiar. As Screen Rant points out, that’s because it’s a mini version of Star Wars' Death Star.

8. JEFF GOLDBLUM SAID “MUST GO FASTER” IN BOTH JURASSIC PARK AND INDEPENDENCE DAY.

Goldblum first uttered the famous line in 1993’s Jurassic Park, then tried it out again in Independence Day—at Emmerich’s request. Steven Spielberg, reportedly, was not pleased.

9. LOTS OF GOLDBLUM’S DIALOGUE WAS IMPROVISED.

According to Devlin, more than half of the dialogue Goldblum exchanged with Will Smith and Judd Hirsch (who played Goldblum’s father) was improvised. For example, most of Goldblum’s and Smith’s lines while they’re navigating the salvaged alien vessel into its enormous mothership were made up on the spot.

10. THE PRESIDENT’S ROLE WAS WRITTEN FOR KEVIN SPACEY, BUT STUDIO EXECS DIDN’T THINK HE WAS STAR MATERIAL.

As co-writer of the film and a childhood friend of Kevin Spacey’s, Devlin initially developed the role of Independence Day’s POTUS with Spacey in mind, but Twentieth Century Fox reportedly wasn’t having it. “We literally had an argument,” Devlin told The Hollywood Reporter, "and the executive, who's no longer there, said he just didn't think Kevin Spacey was a movie star."

11. MATTHEW PERRY DROPPED OUT OF THE FILM. BUT HIS DAD HAD A ROLE.

Film School Rejects reports that the role of Captain Jimmy “Raven” Wilder, which was eventually played by Harry Connick Jr., was originally offered to Matthew Perry. He pulled out before shooting began, though, making his father, John Bennett Perry, who played a Secret Service agent, the only Perry in the film.

12. JAMES BROWN HAD A CAMEO. (AT LEAST HIS VOICE DID.)

According to Devlin, the sound mix accompanying Randy Quaid’s heroic, self-sacrificial plunge into a ship’s weaponry includes a voice clip of the Godfather of Soul himself.

13. THE FILM FACED CENSORSHIP AND PROPOSED BANS IN LEBANON.

The Los Angeles Times’ 1996 review of Independence Day suggested that the film had a serious tendency to “marry schlocky plot elements to a cheerful insistence on stereotyping, among others, Jews, gays, alcoholics, scientists and residents of Los Angeles.” In Lebanon, negative reactions to Independence Day’s presentation of its characters were even greater, and led to censorship and proposed bans of the film.

In November 1996, The Washington Post reported that Lebanese censors trimmed the movie twice under supervision of their Interior Ministry’s Public Security Department, and that many cuts recognized Muslim/Jewish tension in the region. “Gone is the scene in which Judd Hirsch dons a skullcap and leads a group of White House aides and soldiers in a Hebrew prayer for mercy,” wrote Barton Gellman. “Gone, too, is the fleeting footage—a few seconds at most—of Israeli troops working side by side with Arabs in a desert redoubt.”

14. DUE TO LICENSING WORRIES, THE FILM WAS ALMOST TITLED DOOMSDAY.

People’s Choice notes that Fox execs weren’t initially thrilled about using the title Independence Day, the rights to which were still owned by Warner Bros. after the studio’s 1983 film of the same name. Speaking to Complex, Emmerich, Devlin, Pullman, and several of the film’s other key players explained that the ultimate line of Bill Pullman’s humanity-rousing speech was designed to show Fox just how affecting their preferred title could be. According to Pullman:

"[There] suddenly came some interest in pushing up the date in the schedule on when we would shoot the speech, because Fox was considering pushing the title ‘Doomsday.’ That would’ve been a horrible title, and I’ve gone through a couple movies that got stuck with bad titles. So it was urgent to get it in and to have the words, “Today we celebrate our Independence Day” to prove why that had to be the title. I felt the urgency to get it right."

15. THE PRESIDENT’S SPEECH WAS BASED ON SHAKESPEARE’S HENRY V.

“The speech is obviously very derivative of Shakespeare’s Henry V and his St. Crispin’s Day speech before the Battle of Agincourt, where King Henry leads his outnumbered men into battle,” Michael Waldman, who served as Bill Clinton’s Director of Speechwriting from 1995 to 1999, told Complex. “In the Independence Day speech the president says, ‘July Fourth will no longer be known as an American holiday…’ Henry the Fifth says, ‘This day is called the Feast of St. Crispian, he that outlives this day and comes safe home will stand a-tip-toe when this day is named.’ Basically, they took that and rewrote it. Shakespeare wasn’t gonna sue.”

Added Devlin: “Roland turned to me and said, 'Oh great. We only have to write a speech as great as the St. Crispin’s Day speech. How are we going to do that?’ … I said, ‘Let me kind of just vomit out something really fast now and then we’ll spend a lot of time on it later and really rewrite it and make it perfect.’ So I went into the other room and literally in five minutes I whipped the speech out, put it into the script—we didn’t even read it. It was just a placeholder.”

In the end, though, the only change the duo made was the last-minute addition of its final line.

16. IN ALL, THE SCRIPT TOOK JUST FOUR WEEKS TO WRITE.

As the Los Angeles Times noted, Devlin and Emmerich penned the script for the 39th biggest box office hit in U.S. history (adjusted for inflation) in just four weeks. Not bad for a month’s work.