Released 35 years ago today, 1983’s National Lampoon’s Vacation features Chevy Chase in an idiot-defining role as the alarmingly optimistic Clark Griswold, a well-meaning husband and father who is determined to give his family the time of their lives—no matter the cost to life, vehicle, or animal.

The film was an immediate hit, spawning four sequels of increasingly diminishing returns as well as a 2015 Vacation sort-of-sequel, featuring Griswold’s son, Rusty, who appears determined to equal or surpass his father’s mistakes. In celebration of its 35th anniversary, let's have a look at some facts about the family's original trip.

1. THE MOVIE PRETTY MUCH KILLED THE STATION WAGON.

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Griswold’s plan to cart his family from Chicago to California to visit Disneyland stand-in Walley World required a durable vehicle. Obviously, he didn’t get one. The unheralded star of the film is the Wagon Queen Family Truckster, a station wagon with eight headlights and a pea-green finish. The car was actually a Ford LTD Country Squire heavily modified to be as unattractive as possible, and it did the job a little too well: Following the release of Vacation, station wagon sales plummeted. Also known as “estate” vehicles, the models were shortly replaced in popularity by minivans and, later, SUVs.

2. IT WAS BASED ON A RAND MCNALLY ROAD ATLAS.

John Hughes was working at a Chicago advertising agency when he began pestering the editors of the National Lampoon for writing assignments. During a catastrophic blizzard in 1979, a snowbound Hughes wrote a short story, "Vacation ’58," about a Detroit family taking an unfortunate trip to Disneyland. Hughes laid out a Rand McNally road atlas from the trunk of his car and figured out where the family could stop along the way. Warner Bros. purchased the rights to the story as soon as it was published, and Hughes was invited to write the script. (Knowing Disneyland was unlikely to consent to the R-rated material, Disneyland became Walley World.)

3. CHEVY CHASE REALLY NEEDED A HIT.

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Though Chase had made a strong impression in his single year as a cast member on Saturday Night Live, his film career wasn’t the runaway success most had anticipated. Of the six films he made between leaving SNL in 1976 and 1982, only two—Foul Play and Caddyshack—had been hits. Likewise, the publicly-traded Lampoon brand in film had seen just one major home run (Animal House) followed by two bombs, Class Reunion and Movie Madness. Of Class Reunion, Roger Ebert observed that it “has its funny moments, but they’re rare enough that we’re acutely aware of them.”

4. JOHN HUGHES'S SCRIPT HAD TO BE REWRITTEN.

"Vacation ’58" was written by Hughes from the point of view of Griswold’s son, Rusty, which he felt tempered some of the more outlandish moments. (Originally, Clark shoots Walt Disney in the leg.) But casting Chase meant switching the focus to the head of the family; while Hughes shifted the perspective, director Harold Ramis and Chase retooled the script after they felt Hughes had taken the premise as far as he could. Ramis would later say that Hughes was probably a little upset over having his material reworked. “I saw John quoted in an interview saying he was going to start directing his own movies,” Ramis said, “because he was tired of seeing his scripts ruined by other directors.” (Hughes wrote and directed Sixteen Candles in 1984.)

5. THE PRODUCTION SAVED A DOG TIED TO A BUMPER.

One of the particularly morbid gags in the film is when the Griswolds forget that their Aunt Edna’s dog is still tied to the bumper of the Truckster as they drive away. Appearing on Late Night with David Letterman in 1983, Ramis told the host that the crew was staying at a hotel in Durango, Colorado and saw a car begin to drive off with a dog still attached. They were able to stop the driver before the pooch got towed.

6. ANTHONY MICHAEL HALL TRIED PEEPING ON BEVERLY D'ANGELO.

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Hall, 14 at the time he was cast as Rusty, was flirting with puberty during filming, growing three inches before the cast reassembled to shoot scenes after principal photography had wrapped. Prior to that, the actor tried to make himself an on-set presence for a scene in which his onscreen mother, played by Beverly D'Angelo, is naked for a shower sequence. In 2009, Hall told Maxim he was yanked away by a producer but was “totally trying to sneak a peek.”

7. THE "EAST ST. LOUIS" SCENE WAS ACTUALLY ST. LOUIS.

Ramis expressed regret over a scene in which the Griswolds take a wrong turn into East St. Louis, Illinois, having their hubcaps stolen and the Truckster stripped while Clark asks for directions from a local. The area subsequently developed a reputation for criminal activity that wasn’t warranted. Though it doesn’t exactly soften the blow, the scene is actually supposed to take place in St. Louis: The family crosses the Poplar Bridge, and Ramis said a shot that features an East St. Louis sign was placed in the film in error.

8. BORIS VALLEJO PAID HOMAGE TO HIS OWN WORK FOR THE POSTER. 

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Fantasy artist Boris Vallejo was hired to illustrate the theatrical release poster for Vacation. The “king of the hill” style template, with Clark standing triumphantly and raising his tennis racket, was used by both Frank Frazetta and Vallejo for their respective Conan illustrations. Vallejo later stated that the Vacation poster brought him more assignment work than anything he’s done.

9. CHRISTIE BRINKLEY WAS SUPPOSED TO BE RUSTY'S (NUDE) DREAM GIRL.

The Hughes story and script originally had Brinkley’s mystery woman cruising by in a Ferrari and flirting with Rusty. When the focus shifted to Chase, so did her attention. Brinkley was also supposed to strip naked for the movie, but refused; she wound up in a nylon bodysuit that gave off the impression of being topless while in a pool.

10. THEY ENDED UP AT SIX FLAGS.

The film’s climactic trek through Walley World was actually shot at Six Flags Magic Mountain in Valencia, California; Ramis had Chase, John Candy, and other cast members board a roller coaster with a camera mounted to it in order to capture shots on the rides. Dana Barron, who played Audrey Griswold, became so distressed with motion sickness she had to be given repeated doses of Dramamine.

11. THE ORIGINAL ENDING WAS DESPISED BY AUDIENCES.

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Hughes concluded the tortuous Griswold vacation by depicting Clark driving to Roy Walley’s home, bursting in, shooting him in the leg, and then forcing Walley and his cohorts to sing and dance at gunpoint; Griswold was then taken to jail. Ramis shot it as written, but test audiences on the Warner lot proved what Hughes suspected: that a home invasion wasn’t going to play on film. He rewrote the ending—the Griswolds enjoy their own private, bloodless Walley World experience—and Ramis hired Candy to play a security guard for reshoots.

12. IT BEAT RETURN OF THE JEDI AND JAWS 3-D AT THE BOX OFFICE.

Released in a competitive summer movie season, Vacation debuted at number one, muscling out sequels to Jaws and Star Wars—both of which had been out for some time—from the top spot. It was the year’s third highest-grossing comedy, earning $61.4 million: Only Trading Places and Mr. Mom (also written by Hughes) performed better.

13. THE GRISWOLDS REUNITED FOR A SHORT FILM.

Of the various sequels that followed up on the Griswolds over the years, one of the least-known is a 14-minute short film, Hotel Hell Vacation, that was released in 2010 as part of a promotional campaign for a travel rental site. In it, Clark and Ellen get away for a second honeymoon while planning to drop in on their son, Rusty. It will not be confused for a John Hughes film.

14. THERE IS A REAL WALLY WORLD.

They dropped the “e” in “Walley,” but East Park in London, Ontario once had the water ride segment of their property labeled Wally World. In the U.S, Water World in Federal Heights, Colorado has a mini-water attraction meant for children also named Wally World; Marker’s Wally World in Liberty, Indiana offers go-karts and also sells power tools, which sounds like the setup to a punch line only Clark Griswold could deliver.