20 Mind-Boggling Facts About Inception

After The Dark Knight made $1 billion worldwide, Warner Bros. let director Christopher Nolan to make his passion project, Inception (although most passion projects don’t generally have a budget of $160 million). The confusing-but-exhilarating film, which was released on July 13, 2010, made more than $800 million worldwide. Here are some things you might not know about the film.

1. Christopher Nolan toyed with the idea of making Inception a horror movie.

Christopher Nolan both wrote and directed Insomnia. He originally came up with the idea in the early 2000s, after he finished making Insomnia. Originally, he considered using the same concept, but as a horror film.

2. The main characters in Inception each represent a key part of the filmmaking process.

Each character represents a vital part of the film industry. “The Point Man” (Joseph Gordon-Levitt as Arthur) is the producer; “The Architect” (Ellen Page as Ariadne) is the production designer; “The Forger” (Tom Hardy as Eames) is the actor; and “The Mark” (Cillian Murphy as Robert Fischer) is the audience. As for Leonardo DiCaprio as Dom Cobb, he’s a stand-in for the director, giving him obvious parallels to Nolan. “I can lose myself in my job very easily," Nolan told Entertainment Weekly. "It’s rare that you can identify yourself so clearly in a film. This film is very clear for me.”

3. Christopher Nolan didn’t research dreams while writing the screenplay for Inception.

He took a similar approach to writing a movie about dreams as he did to writing Memento, a movie about memory. He primarily used his own experiences and feelings rather than outside information. “I think a lot of what I find you want to do with research is just confirming things you want to do," Nolan told Collider. "If the research contradicts what you want to do, you tend to go ahead and do it anyway. So at a certain point I realized that if you’re trying to reach an audience, being as subjective as possible and really trying to write from something genuine is the way to go. Really it’s mostly from my own process, my own experience.”

4. Christopher Nolan had to convince the studio that the various dream layers in Inception would be as minimally confusing as possible.

He told them, “One of the dream levels is in the rain, one of them is a night interior, one is outdoors in the snow ... even in a close-up, you would be able to tell which level you were in as you cross-cut.”

5. Inception's casting decisions revolved around Leonardo DiCaprio.

Nolan knew that he wanted Leonardo DiCaprio for the role of Cobb, so according to him, “We were just trying to cast the best people I could find for those parts, who felt right around Leo.” This also involved casting a young ensemble because Nolan “wanted to get a young, energetic cast around him who wouldn’t make look younger.”

6. Leonardo DiCaprio worked with Christopher Nolan to make Inception more character-driven.

“Once Leo came on board, I spent months and months sitting with him and discussing the script," Nolan told The Hollywood Reporter. "He made some extraordinary contributions to the script and really challenged me to make the script clear, but also to follow its interior logic and really be true to the essence of the characters and the rules we set out.”

Nolan’s wife and producing partner, Emma Thomas, said that “the work did on his character with Chris made the movie less of a puzzle and more of a story of a character audiences could relate to.”

7. Ellen Page didn’t have to audition for Inception.

She met with Nolan for a sit down that had nothing to do with the film. The next week, she was asked to read the script for Inception. She had to read it in an office, not at home. Luckily, she loved the character and Nolan gave her the role.

8. Ariadne is named after the daughter of Minos in Greek mythology.

It’s a unique name for a modern day character, but it makes complete sense for the part. In one story, Minos actually has Ariadne take control of a labyrinth. In the film, the labyrinth that Ariadne draws for Cobb’s test is very similar to paintings of the ancient character’s labyrinth. Nolan acknowledges this connection. “I wanted to have that to help explain the importance of the labyrinth to the audience," he told Wired. "I don’t know how many people pick up on that association when they’re watching the film. It was just a little pointer, really. I like the idea of her being Cobb’s guide.”

9. Inception was filmed in locations around the world.

The rotating set that Arthur flies through was created in Bedfordshire, England. Calgary, Alberta was the location for the epic mountain scenes. They also did shoots in Morocco, Tokyo, London, and Los Angeles. Overall, they ended up filming in six different countries.

10. Christopher Nolan considered filming Inception in 3D.

Eventually, though, Nolan determined that they would be “too restricted by the technology.” After filming, they almost converted the movie to 3D in post-production, but there simply wasn’t enough time.

11. Christopher Nolan wanted the explosions in Inception to look surreal, rather than the standard Hollywood orange flames.

Shooting guidelines in Paris frowned upon the use of actual explosions. So, the crew used high-pressure nitrogen, which they set off right near the cast. Said special effects coordinator Chris Corbould, “When we let an explosion off behind an actor, you get a very different reaction from when he is standing in front of a green screen and someone yells, ‘Explosion!’” More debris was added and the explosions were enhanced in post-production.

12. The paradoxical stairs in Inception were inspired by the art of M.C. Escher.

Nolan wanted to build a paradoxical staircase that worked, but it wasn't possible. So, they built a staircase that just ended abruptly. In order to make them look like a paradox on camera, the crew turned to a visual effects team. According to Paul Franklin, the Visual Effects Supervisor, “These steps have to be built in such a way that when you view them from one angle, the top most level of the staircase lines up with the bottom most level of the staircase. And so what visual effects is able to do is we’re able to make computer models of this and work out exactly the dimensions of the steps that have to be built and where the camera has to be in three-dimensional space to be able to film it.”

13. Christopher Nolan's production team built sets that shifted and rotated for Inception.

During the scene in which Cobb explains to Fischer that they are in a dream, he proves it by letting the room shake and shift. To pull it off, the crew moved the set 25 degrees while filming, without any of the props moving. “The entire set would be shifting," DiCaprio said. "We had to hold onto the actual set so we didn’t slide off.”

For the scenes in which Arthur is floating around the hotel without gravity, Joseph Gordon-Levitt wasn’t acting in front of a green screen or placed in zero-gravity. The crew actually built the set so it could rotate a full 360 degrees. Then, they would suspend Gordon-Levitt from a wire to get their shots. It took 500 people and three weeks to film all those scenes. Gordon-Levitt only used his stunt double for one shot.

14. Inception's actors had an easy way of telling which level of the dream world they were supposed to be in during a particular scene.

“It was easy to orientate which dream sequence I was in because of my costume," Tom Hardy told Collider. "If in doubt, I could just look at my shoes and say, ‘Oh! I know which dream I’m in.'"

15. Inception's mountain set was built into the side of a mountain.

The set, built into a mountainside in Alberta, had no snow at the time. In fact, the crew was starting to get concerned that they wouldn’t end up having any snow by the time the shoot started. “The art department kept sending us pictures of mud," Thomas said. "The week before we went up there, we still had no snow.” But that wasn’t a problem for long. They ended up shooting in the middle of blizzards after the biggest storm of the decade.

16. The Inception scene in which the van falls off the bridge in slow motion took months to shoot.

According to Dileep Rao, who played the driver Yusuf, “We’d shoot it one day, go off and shoot something else. Then shoot another piece of . It was so complex and there were so many locations and so many different moves I have to do. It’s the stuff that makes or breaks that last sequence.” For the underwater portions, actors were holding their breath for up to five minutes at a time, with the occasional top off from a SCUBA tank. As for how they got the van to fall off the bridge? It was shot out of a cannon.

17. Though many special effects were handled on set, Christopher Nolan still had a lot of work to do in post-production on Inception.

For instance, Franklin said, “Getting the bits and bobs to fall out of the hotel cleaning trolley ? That’s one guy—months of lonesome work.” And a team of CGI specialists worked on the “Limbo City” scenes with DiCaprio and Page for nine full months.

18. Christopher Nolan finished both early and under budget.

He actually prefers the constraints that time and money give him, so he makes a serious effort to be efficient when it comes to filmmaking.

19. Christopher Nolan hasn’t said much on Inception's ambiguous ending.

In 2010, Nolan told CNN that the film was intentionally left that way, so he has no desire to add to the conversation. “There can’t be anything in the film that tells you one way or another because then the ambiguity at the end of the film would just be a mistake," he said. "It would represent a failure of the film to communicate something. But it’s not a mistake. I put that cut there at the end, imposing an ambiguity from outside the film. That always felt the right ending to me."

Michael Caine has his own interpretation of the ending that he hasn’t been shy with, though. He claims that the ending is undoubtedly real, not a dream. “ drops at the end, that’s when I come back on," Caine told ScreenRant. "If I’m there it’s real, because I’m never in the dream. I’m the guy who invented the dream.”

20. Film scholars have a lot of different theories about Inception.

Some of these include: it was all a dream, Saito is the actual architect, and Cobb is dreaming/not dreaming/dead at the end of the film.

A version of this story ran in 2015; it has been updated for 2021.