1. Studio Executives tried Tricking Director Mel Brooks into Shooting the Film in Color

By the mid-‘70s, black and white cinema was an endangered species. Nevertheless, Brooks felt strongly about replicating the feel of Universal’s classic Frankenstein films by going colorless. However, not everybody shared his vision. Columbia Studios’ brass thought the style was unmarketable and, as Brooks explains in this delightful interview (skip to 47:40), used some slippery tactics in an attempt to get their way:

“They said ‘Okay, we’ll make it in black and white, but on color stock so that we can show it in Peru, which just got color. And I said ‘No. No because you’ll screw me. You will say this and then, in order to save the company, you will risk a lawsuit and you will print everything in color. It’s gotta be on… black & white thick film.”

Thankfully, Brooks prevailed, though 20th Century Fox wound up taking charge of the project.

2. Star and Co-Writer Gene Wilder Convinced Brooks to Forgo his Usual Cameo Appearance

Like Alfred Hitchcock, Brooks usually gave himself a part in his own films, from Blazing Saddles’ loopy governor to the wine-selling Rabbi of Robin Hood: Men in Tights. These characters regularly broke the fourth wall and “winked” at the audience, something Wilder felt would clash with Young Frankenstein’s tone. So, as a condition of his taking on the lead role, Wilder made Brooks agree to remain off-camera.

However, the director did provide some howling:

As Frederick Frankenstein (Wilder) takes his first ride to the family castle, the distant wolf cry which startles him is a sound Brooks actually vocalized himself.

3. Early On, We Hear the Exact Same Conversation Repeated in Both English and German

En route to Romania, our protagonist catches a train to New York, whereupon he hears an American couple bickering. In the very next scene, Frederick (now on a Transylvania-bound locomotive) witnesses a European pair having an identical, word-for-word exchange in German

4. One of Igor’s Best Moments Inspired a Hit Aerosmith Song

“Walk this way!” Marty Feldman’s Igor instructs his master, who proceeds to copy the hunchback’s shuffling gait. Aerosmith frontman Steven Tyler found this line hilarious and repurposed it as the title of a track about high school lovers.

5. Hans Delbrück Was a Real Person

As Frederick readies his monster, he sends Igor to fetch a very special brain which rests in a jar labeled “Hans Delbruck: Scientist and Saint”. The actual Hans Delbrück (1848-1929) was an accomplished military historian whose son, Max, won a Nobel Prize for his work with viruses.

6. Several Props Had Previously Appeared in the Masterful 1931 Frankenstein Film

Taking his feature-length tribute to the next level, Brooks included much of the faux lab equipment used in that earlier picture.

7. Teri Garr Based Her Character’s Voice on Cher’s Hairdresser

Garr made several appearances on The Sonny and Cher Comedy Hour and used Cher's German wig-stylist as a model for ditzy lab assistant Inga’s heavy accent.

8. Brooks Hired Kenneth Mars After the Actor Signed Off on an Odd Costuming Choice

The two had already collaborated in 1968’s The Producers, and while casting Young Frankenstein, Brooks offered Mars the role of grumpy Inspector Kemp, but not before pitching an eccentric wardrobe gimmick that ultimately wound up on-screen.

“He [said],” Mars later reminisced, “‘Let me ask you this… if you’re wearing an eye patch and you’ve got a monocle on top of the eye patch, is that too much?’ I said ‘Of course not.’ He said ‘Good, you’re hired!’”

9. Gene Hackman Specifically Asked Wilder for a Part in Young Frankenstein Because he “Wanted to Try Comedy”

According to the movie’s Blu-Ray commentary, Hackman—who’d been thrice nominated for an Academy Award (and won one in 1971)—learned about Young Frankenstein through his frequent tennis partner Wilder and requested a role. Ultimately, ‘Harold’—the lonely blind character he briefly portrayed—sparked one of the most memorable sequences in comedic history.

10. Peter Boyle Had to Wear a Special Pad Over His Crotch to Avoid Getting Scalded During the Famous Blind Man Scene

During their hysterical encounter, sightless Harold winds up accidentally dumping a bowlful of hot soup onto the poor creature’s lap. Fortunately, Boyle’s protective gear kept him from having to method act his way through the ordeal.

11. A Huge Percentage of the Movie Had to Be Deleted

“For every joke that worked, there were three that fell flat,” says Brooks, who whittled Young Frankenstein down to its current runtime after observing several mixed reactions from test audiences. This cut material included a clip in which Frederick’s relatives listen to a recorded will left by his great grandfather Beauvort von Frankenstein whose message starts skipping and nonchalantly repeats the phrase “Up Yours!”

In addition, the “Puttin’ on the Ritz” number was nearly axed as well. Brooks reportedly felt that having Dr. Frankenstein and his monster tap dance to an old Irving Berlin song seemed “too crazy.” Hearing this, Wilder—who though it brilliant—snapped and came “close to rage and tears” before Brooks unexpectedly changed his tune. “I wanted to see how hard you'd fight for it,” said the director, “And I knew if you fought hard enough, it was right...You did, so it's in.”

12. Wilder was Constantly Cracking Up During Takes

According to Cloris Leachman, “He killed every take [with his laughter] and nothing was done about it!” Shots would frequently have to be repeated as many as fifteen times before Wilder could finally summon a straight face.

But, to be fair, he certainly wasn’t the only one who couldn't always keep it together.

Young Frankenstein sees Marty Feldman’s comic genius on full display, which was often more than his castmates could handle. For example, the scene where Frederick’s fiancée Elizabeth (Madeline Kahn) greets him at the castle generated a lengthy gag reel because Feldman—whose character starts ravenously gnawing on her mink scarf—kept everyone in stitches with his manic over-acting.

13. Brooks’ Blazing Saddles and Young Frankenstein were the 1st and 3rd highest-grossing films of 1974, respectively

“It’s good to be the king!” Before this pivotal year, the funnyman’s earlier efforts—The Producers and The Twelve Chairs (1970)—netted mixed reviews and had lackluster box office performances. But after turning out these back-to-back hits at breakneck speed, Brooks’ reputation as one of Hollywood’s greatest comedic directors was secured.

14. Leachman Was Asked to Reprise Her Role for the 'Young Frankenstein' Musical

After getting eliminated from ABC’s Dancing with the Stars, Brooks offered the 82-year-old actress a chance to take a second stab at playing Frau Blücher for his on-stage Young Frankenstein musical, but the show’s run ended before her schedule freed up.

15. Throughout the Shoot, Brooks Offered Wilder Directing Advice

Knowing his star dreamed of one day sitting in the director’s chair, Brooks made a point to give him as many pointers as possible before shooting concluded. Wilder reminisced, “Mel would say, ‘Do you know the trouble I’m in because I didn’t shoot that close-up? Don’t do that.’ I would say, ‘To whom are you talking?’ ‘You, when you’re directing.’”

Though both headed various productions after Young Frankenstein, they’d never collaborate on another flick. Nevertheless, the pair’s shared legacy is unimpeachable. All three of Brooks’ movies in which Wilder appeared—The Producers, Blazing Saddles, and Young Frankenstein—have been selected for preservation by the National Film Registry and included on the American Film Institute’s “100 Funniest Movies of All Time” list.