Executive produced by Steven Spielberg, co-written by Michael Crichton, helmed by the director of Speed, and loaded with impressive (for 1996) special effects, Twister was a box office hit, sucking up nearly $500 million in worldwide ticket sales, making it the second biggest hit of 1996 (Independence Day took the top spot that year).

The film starred Bill Paxton and Helen Hunt as an estranged couple who find themselves thrown back together to chase some tornadoes and try to successfully put their DOROTHY data-gathering instrument into action before a competing research team rips their invention off, all the while putting their co-workers in grave danger. To celebrate Twister's 20th anniversary, here are some facts about the hit action film.

1. IT WAS BASED ON HIS GIRL FRIDAY.

The screenplay was credited to Michael Crichton and his wife, Anne-Marie Martin. When screenwriter Stephen Kessler sued Spielberg, Crichton, Warner Bros., and Universal Studios for plagiarism in 1998, Crichton testified that he and Martin based their Twister script on a PBS Nova episode on tornado chasers in Oklahoma, as well as the plot to His Girl Friday. A Los Angeles Times article that ran a few weeks after Twister's release noted the similarities between Twister and the Rosalind Russell/Cary Grant gender-switching remake of The Front Page (1931). Kessler eventually lost the case.

2. JOSS WHEDON WORKED ON THE SCRIPT (THOUGH HE DIDN'T GET A CREDIT).

Joss Whedon had to leave production twice, once because of bronchitis and again to get married. Of the film, Whedon said, "there are things that worked and things that weren't the way I'd intended them."

Once the filmmakers realized a lot of the movie would have to be set in moving vehicles, they brought in Jeff Nathanson (who later wrote Catch Me If You Can and The Terminal for Spielberg) to write car dialogue. "I had to write dialogue for the cars like 'Look out' and 'Here it comes' and 'Get out of the way,'" Nathanson explained.

Steven Zaillian (who won an Oscar in 1994 for writing Schindler's List) had a unique experience; he worked on the movie for three weeks without getting a single word in the script. "For three weeks I wrote scenes and faxed them to Oklahoma, where the film was being shot," he explained. "Unbeknownst to me [until] much later, every page I sent was completely ignored because the director was perfectly happy with the script he already had. The production company was not. Anyway, the point is, there isn't a word I wrote for Twister that actually made it into the film."

3. PHILIP SEYMOUR HOFFMAN TOOK THE JOB SO THAT HE COULD MOVE BACK TO NEW YORK.

Philip Seymour Hoffman played Dusty in the film. When asked about his reasons for making it, he told Esquire, "I was living in L.A. at the time ... and I knew if I took that job, I'd be able to move back to New York."

4. GARTH BROOKS TURNED DOWN THE LEAD ROLE.

According to a lawsuit by a former employee of the country music singer, Garth Brooks turned down the lead in Twister because the tornado was the real star.

5. BOTH HELEN HUNT AND JAN DE BONT WALKED AWAY FROM OTHER MOVIES TO WORK ON THIS ONE.

Helen Hunt (Dr. Jo Harding) passed up working with John Travolta in John Woo's Broken Arrow (1996). After more than six months of pre-production, de Bont left his Godzilla (1998 version) directing gig because of studio feuds over the budget and immediately agreed to direct Twister instead.

6. HELEN HUNT AND BILL PAXTON WERE BRIEFLY BLINDED.

The stars sat in the cab of a truck lit with bright electric lamps all day long. To keep the sky behind them looking dark and stormy as it got brighter outside the truck, the lamps were made even brighter—so bright that they temporarily blinded Paxton and Hunt. The two needed to use eyedrops and wear special glasses for a few days afterward.

There were other accidents, too. Hunt and Paxton both needed hepatitis shots following an afternoon in an unsanitary ditch. De Bont said Hunt could be "a little bit clumsy" after she accidentally hit the side of her head on a car door. "Clumsy?" Hunt retorted. "The guy burned my retinas, but I'm clumsy."

7. SOME OF THE CREW QUIT ON DE BONT.

De Bont allegedly pushed a camera assistant into the mud after he got in the way of a complicated shot, and told director of photography Don Burgess (Forrest Gump) and his team that they were "incompetent." In response, Burgess and more than 20 camera people walked off the set.

The director denied calling the team "incompetent" and explained to Entertainment Weekly that he pushed the assistant in a bout of frustration. "With the wind machines it was very loud,” de Bont said, ”so the crew had to watch my hand signals. I cued action, and he [walked] right in the middle of the scene. We kept losing good performances because of stupid things like that. I don’t think I’m a hothead, but I do believe you have to be passionate. These crews get paid well, and when they screw up, I’m going to call them on it.”

8. WAKITA, OKLAHOMA WAS ONE OF THE MOVIE'S BIGGEST STARS.

Wakita (pop. 344) was chosen as one of the film's main locations when scouts noticed there was debris still left over from a big June 1993 hailstorm. Most of the residents signed up to be extras and were paid $100 per day.

Wakita is now home to the Twister (The Movie) Museum, which opened up a few months before the film's release. There's also a five-block walking tour, plus a Dorothy I prop and a Twister pinball machine (a gift from Paxton).

9. THE TORNADO SOUNDS ARE MADE UP OF VARIOUS ANIMAL NOISES.

According to Variety, an altered recording of a camel's moan helped create the storm sounds. It was reported elsewhere that a lion's growl and a tiger's snarl were remixed as tornado audio.

10. A BOEING 707 JET WAS USED TO GENERATE THE WIND.

In addition to the aircraft, the production utilized a small "battalion" of wind machines. Even though 200 mph winds were blowing around them, stunt doubles were used only some of the time. The actors used earplugs, but—apparently not learning their lesson earlier—did not use eye protection. "After every shot, someone would come around with the Visine,'' Hunt explained.

11. PRODUCTION ON MAD ABOUT YOU HAD TO BE DELAYED SO THAT HUNT COULD FINISH THE MOVIE.

Production for season four of the NBC sitcom starring Paul Reiser and Hunt was delayed two weeks. NBC executives told The New York Times they believed production was delayed because Reiser and the rest of the Mad About You team were busy "sulking" over being moved to Sunday nights.

12. "IT SUCKS" WAS CONSIDERED AS A TAGLINE.

Producers changed their minds when they realized that such a tagline would be grist for any critic or moviegoer who didn't like the movie.

13. OPRAH HUMILIATED THE CAST (PROBABLY NOT INTENTIONALLY).

"The biggest thing that I remember from when we were doing press for the film was that we went on Oprah," Jami Gertz (Dr. Melissa Reeves) recalled to The A.V. Club. "We came out individually, and we were talking about how tough it was to shoot. We would get debris in our eyes from the wind machines and we’d have to use the eye wash. And sometimes when we were in the makeup trailer, we’d have to turn off the electricity, because we were close to an electrical storm and we didn’t want to get electrocuted, and blah blah blah. And then she breaks for commercials, and then she comes back and says, 'And now for survivors of real twisters!' [Laughs] So here are all these actors, these dopey actors on stage, and now we have these people who are like, 'I was burned, lightning hit me ...' And we’re like, 'Uh, no, that didn’t happen to us. Oooh.' It was just so humiliating. Here are these real survivors of twisters, and we’re just the pretend movie version."

14. BILL PAXTON THINKS THEY MADE THE "PEPSI LITE" VERSION OF THE MOVIE.

"I’d love to direct a sequel to that movie," Paxton said. "I’ve always felt like there was a Jaws version of that movie. I always felt like we did the Pepsi Lite version of that movie."

15. SPIELBERG OFFICIALLY ATTRIBUTES THE FILM'S SUCCESS TO ITS SPECIAL EFFECTS, NOT ITS STORY.

Variety reported that Spielberg, in his testimony during the plagiarism trial, said that the special effects—and not the writing—were the reason for Twister's success.