1. After working on M. Night Shyamalan's Fox series Wayward Pines, brother writing duo Matt Duffer and Ross Duffer came up with the concept for Stranger Things, though it was initially called Montauk.
"It's very hard when your brain is latched onto a title, it's really, really hard to get people to agree and accept another title," Matt told The Daily Beast in 2016. "Initially when we came up with this title Stranger Things, it was hard for people to embrace."
2. The Duffers envisioned filming the series on Long Island, but it ultimately proved to be too challenging.
"We liked Montauk, because we liked the coastal setting, and Montauk was the basis for Amity, and Jaws is probably our favorite movie, so I thought that that would be really cool," Matt explained to The Hollywood Reporter. "Then it was really going to be impossible to shoot in or around Long Island in the wintertime. It was just going to be miserable and expensive."
Atlanta ultimately became the home base for production.
3. Before Netflix picked up the series, almost 20 networks passed on the project, according to Vulture, with executives believing audiences would not be able to invest in a show starring four children.
4. To play Eleven, then 12-year-old Millie Bobby Brown had to say goodbye to her hair.
"The day I shaved my head was the most empowering moment of my whole life," the actress reflected during PaleyFest in 2018. "The last strand of hair cut off was the moment my whole face was on show and I couldn't hide behind my hair like I used to. As I looked in the mirror I realized I had one job to do: inspire...You don't need hair to be beautiful."
5. She drew inspiration from Charlize Theron in Mad Max: Fury Road, as well as costar Winona Ryder's old yearbook photos.
"Winona looked cool back in the day with the pixie cut," she shared, "and I thought maybe I could bring it back!"
6. The British actress revealed she turned to a surprising source to perfect her American accent: Miley Cyrus' Hannah Montana. "It's so goodt," she told Jimmy Fallon during a visit to The Tonight Show. "Like the film, everything. Everything about it is amazing. And I got the American accent."
7. To find their four main kids, the Duffer brothers had the young actors audition with scenes from Stand By Me.
8. When it came to finding their Mike, the brothers had a different idea for the character. That is, until Finn Wolfhard auditioned.
"Originally Mike was a sigher, he was a dreamer, he was much more like Mikey in The Goonies in a lot of ways," Matt told The Daily Beast in 2016. "But Finn had this really anxious, twitchy energy about him and we thought that that was really great and we just kind of wrote the character to match him and his personality."
9. Another actor who influenced his character was Gaten Matarazzo as Dustin. As Matt explained, "I don't think we really understood who that character was. He started out more like a stereotypical nerd and then we met Gaten and we basically tailored the show to him."
10.Thanks to Eleven's affinity for Eggo waffles, Kellogg's saw a significant increase in sales after the show. The company said consumption was up 14 percent in late 2017 after season two was released and October saw the most mentions of the product on social media in a single month.
11. In early 2018, David Harbour went viral after he fulfilled a fan's request to take her senior portraits with her after. She tweeted, "How many retweets for you take my senior photos with me," to which he replied, "25k. And I get to wear the school sweatshirt and hold a trombone." The actor held true to his word.
As he wrote on Instagram at the time. "Voted most likely to hijack someone's high school senior photos 24 years later."
12. Later that year, Harbour was once again up to his social media shenanigans, this time officiating a viewer's wedding in exchange for 125,000 retweets and the first slice of cake. He got ordained and performed her marriage ceremony dressed as Chief Hopper.
13. Many fans theorized that Eleven could be Hopper's daughter, though he eventually became her surrogate father. And in a sweet Easter egg, Eleven was seen wearing the blue braided bracelet Hopper always wore, made from his late daughter's hair ribbon, at her school dance in the season two finale.
14. Eleven's season one kiss with Mike was Millie's first kiss ever. "It was a strange experience," she admitted, "Having 250 people looking at you kissing someone is like, 'Whoa!'"
15. And when the pair had to smooch again the following season, she revealed what her costar whispered in her ear.
"He wanted to let me know he was, like, kissing me then," she explained during a 2017 appearance on The Tonight Show. "So he was like, 'I'm coming in,' and he was like a ventriloquist! It was the craziest thing."
16. Natalia Dyer and Charlie Heaton, who play love interests Nancy and Jonathan, began dating in 2016, but have mostly kept their relationship private.
"That's something important to me—with my family, with my friends, I really like to keep it for me," Natalia told Refinery 29, though she did admit, "It's an interesting thing to work with somebody who you go home with. It's always really fun."
17. Believe it or not, Joe Keery's well-coiffed Steve Harrington was not supposed to make it out of season one alive.
But, "we fell in love with him during the making of season one, which is why we ended up writing that arc for him where he's helping to save the day with Jonathan and Nancy," Ross told The Hollywood Reporter. "Steve was supposed to be this jocky douchebag, and Joe was so much more than that."
18. Also slated to perish was Eleven. Yes, really.
"Eleven was going to sacrifice herself to save the day," Ross said in the 2018 book Stranger Things: Worlds Turned Upside Down. "That was always the end game. But once we realized that the show was potentially going to go on longer than one season, we needed to leave it more up in the air, because deep down we knew the show just wouldn't really work without Eleven. And at that point, we knew how special Millie was. If there was going to be more Stranger Things, Eleven had to come back."
19. The seventh episode of season two—titled "The Lost Sister"—almost never made it to air, with the Duffer brothers telling Vulture they were concerned the outing, which centers on Eleven going off to find another child who was experimented on, would break up the story's pacing.
"When we got to the point of writing the episode, we wanted to see if we really needed it or not," Matt explained. "We actually did toy with pulling the episode completely, but then the ending with Eleven didn't work at all. It just didn't land at all. Then we ended up deciding we needed it."
20. Eleven's sibling was written to be a boy, with the episode originally titled "The Lost Brother."
But after the audition was opened up to all young actors, it was Linnea Berthelsen who landed the part, and the episode ultimately featured Eleven meeting her "sister" Kali.
"Linnea and Millie really had a connection," Matt said, "Millie was like, 'I want to do this with Linnea.'"
21. Bridgerton actress Nicola Coughlan initially auditioned for the role of Robin before booking the role of Penelope Featherington years later. Maya Hawke ultimately nabbed the part, with Nicola saying Hawke was "was far better than I ever would have been."
She added, "It's a good lesson to actors: Watch the stuff you didn't get, because you'll totally understand how it's not personal. You're just right for some things and you're not right for other things."
22. Before playing Sarah on Netflix's Outer Banks, Madelyn Cline appeared in season two as Hawkins High school mean girl Tina.
23. To win the part of Billy, the mullet-rocking bad boy older stepbrother of Max (Sadie Sink), Australian actor Dacre Montgomery filmed a fun, yet slightly raunchy, audition tape, telling GQ he "wanted to make a bit of a splash with the Duffers."
That meant filming himself dancing to classic 1980s songs like "Come on Eileen" and "Hungry Like the Wolf" in nothing but a G-string. Dacre admitted he had some hesitation about sending it, saying, "Either I'm never going to work again, or somebody somewhere is going to see one thing in me, and they'll give me a chance." Fortunately, his risk paid off.
24. Heading into season three, Deadline reported that the cast received major pay increases, with the younger cast going from about $30,000 per episode to more than $200,000 per episode, and possibly even $250,000. Winona and David, meanwhile, were reportedly taking home about $300,000 to $350,000 per episode, while Natalia and Charlie were making $100,000 to $150,000 per episode.