In the sci-fi classic Logan's Run—which was released 40 years ago today—the human population lives under a domed city near Washington D.C. in the year 2274. The utopian setting becomes dystopian once we discover that people are terminated as soon as they turn 30 years old. "Runners" try to escape termination, with the police—a.k.a. the Sandmen—always in pursuit. When Jessica 6 (Jenny Agutter) tries to escape the city to find a mythical Sanctuary, a Sandman named Logan 5 (Michael York) goes after her and begins to question everything he thought he knew.

1. THE MOVIE OWES ITS EXISTENCE TO THE SUCCESS OF WESTWORLD AND SOYLENT GREEN.

Only after Soylent Green and Westworld found success at the box office did the powers-that-be at MGM believe that William F. Nolan and George Clayton Johnson's book, Logan's Run, could work as a movie.

2. MICHAEL YORK HAD TO BE TALKED INTO STARRING IN THE FILM.

York initially didn't think the movie was for him. "But this young member of the [Ahmanson Theatre] company was deputed to drive me back and forth, so we would chat all the time," York told Den of Geek. "I mentioned that I’d had this script, and he asked to take a look at it, so I said 'Of course.' He came to pick me up the next day practically wagging a finger at me saying ‘You’ve got to do this—you may not be aware of it, but it’s pressing a lot of buttons.' And he was absolutely right."

3. YORK, IN TURN, BROUGHT FARRAH FAWCETT ABOARD.

York was playing tennis and saw what he described as a "blonde vision of delight." It turned out to be Farrah Fawcett-Majors. York suggested her to the casting director and she subsequently landed the role of Holly. Fawcett, of course, would become famous starring on Charlie's Angels, which debuted three months after the release of Logan's Run.

4. THERE ARE A FEW KEY DIFFERENCES BETWEEN THE BOOK AND THE MOVIE.

All inhabitants in the book die at the age of 21, not 30. It's set in 2126 A.D., not 2274. The Old Man was a 42-year-old man named Ballard, who turned out to be Francis. "The loss of Ballard, head of our Sanctuary people, disturbed me—and I liked our ending better than theirs," Nolan said. "Still, I'm pragmatic about Hollywood. As an adaptation, it could have been much, much worse."

5. SOME OF THE MAIN ACTORS WOULD HAVE BEEN IN A LOT OF TROUBLE IN THE LOGAN'S RUN UNIVERSE.

York, Richard Jordan (who played Francis), and Michael Anderson, Jr. (who portrayed Doc) were all over the age of 30 when they made the film. (And yes, Michael Anderson, Jr. is the son of the film's director, Michael Anderson.) Fawcett was 29 when the movie was released. Jenny Agutter was 23.

6. THE GUNS DIDN'T WORK ALL THE TIME.

"Those wretched guns misfired as much as they fired," York recalled. "There were a lot of highly technical things, yes, but thank God we weren’t standing against blue-screen all the time."

7. PETER USTINOV IMPROVISED MOST OF HIS DIALOGUE.

"It was a sheer delight to be around Peter for numerous reasons," York said. "For one thing, he was one of the most legendary raconteurs, so his stories were extraordinary—not to mention his delivery of the stories. That funny old man with his story about cats … [Ustinov] was onto Cats way before Andrew Lloyd Webber got hold of T.S. Eliot."

The cats in Ustinov's scene actually lived on the set. To ease the boredom, Ustinov made cat drawings for Agutter. One was called "Cat-tastrophe," and featured a squished cat. Another was of a zombie feline, titled "Cat-atonic."

8. JESSICA 6 WASN'T CRAZY ABOUT HER ATTIRE.

Regarding the character and the outfits she had to wear, Agutter said, "Logan’s Run was fairly embarrassing, but I’m thrilled that I’ve been a part of it all."

9. SOMEONE SNUCK IN A VULCAN SIGN.

A man who claimed to be the extra who flashed the Star Trek Vulcan sign at the end of the movie said he was sent by his mother, a Dallas talent agent, to be one of the men and women to gather around Ustinov. "I was simply wanting to find a way to locate myself in the crowd and didn't do it long, I thought. I feared it would get noticed and end up on the cutting room floor, but ... [it] made the final print. I had forgotten about this until a friend of mine from back then called me and said the salute had made the internet."

10. THERE WAS A BRIEF CBS SERIES, AND RYAN GOSLING WAS SET TO STAR IN A REMAKE.

Logan's Run, the TV series, lasted for 14 episodes from September 1977 to February 1978.

A remake at Warner Bros. was announced as early as 2005. Ryan Gosling was set to star, but left the project in 2012. Earlier this month, Warner Bros. confirmed that they were still moving forward with a Logan's Run reboot.