Pacific Rim is a 2013 American science fiction action movie directed by Guillermo del Toro and starring Charlie Hunnam, Idris Elba, Rinko Kikuchi, Charlie Day, Burn Gorman, Robert Kazinsky, Max Martini and Ron Perlman. The screenplay was written by Travis Beacham and del Toro from a story by Beacham. Take a look below for 27 more interesting and fascinating facts about Pacific Rim.

1. The movie is set in the future, when Earth is at war with the Kaiju, which are colossal sea monsters that have emerged from an interdimensional portal at the bottom of the Pacific Ocean. In order to fight the monsters, humanity unites and created the Jaegers, which are gigantic humanoid robots that are controlled by at least two pilots.

2. While the movie underperformed at the box office in the United States, it was highly successful in other markets.

3. Pacific Rim earned a worldwide total of more than $411 million, $114 million in China alone, becoming Guillermo del Toro’s most commercially successful movie to date.

4. Approximately a hundred Kaijus and a hundred Jaegers were designed, but only a fraction of them appeared in the movie. Every week, the filmmakers held a vote for their favorites.

5. When little Mako is in the alleyway, every object on the set was rigged to the same hydraulic system. Whenever the giant monster was to take a step, everything bounced or shook in unison, including the puddles.

6. “Kaiju” is a Japanese word that literally translates to “strange beast.” It’s usually used to refer to giant monsters from Japanese science fiction movies, such as Godzilla.

7. Screenwriter Travis Beacham also wrote the graphic novel Pacific Rim: Tales from Year Zero. Released along with the movie, Tales from Year Zero serves as a prologue to the movie and is set 12 years before its events.

8. Travis Beacham got the idea for the movie while walking along the California coastline on a foggy morning. The shape of the pier looking like a creature rising from the water, and he imagined a large robot waiting on the shore to fight it.

9. The sound for the Kaiju’s roars were made of layer upon layer of animals roars and growls, which were filtered, sped up, and slowed down to create the roar of alien behemoths. Then, to add emotion and a sense of intelligence, supervising sound editor Scott Martin Gershin and Guillermo del Toro added samples of their own voices.

10. Visual effects supervisor John Knoll and Guillermo del Toro spent several weeks discussing the physics of the giant characters and went into very specific detail, such as how the air displacement from a Jaeger moving between skyscrapers would shake the building’s windows.

11. Though the giant monsters were always intended to be computer generated, all of their designs were expanded form the notion that they could be “worn as suits,” like in traditional Kaiju movies.

12. In Hungary, trailers for the movie couldn’t mention the name of the main robot, Gipsy Danger, because it was offensive to the Roma, a large ethnic group in the country. The name is spoken freely in the Hungarian dubbed version, but it’s left in English. It’s a reference to a type of airplane engine, not the people in question.

13. Karloff, one of the Kaiju from the opening sequence, is named after Boris Karloff. The nickname was given because the creature’s head resembles the desiccated face of Karloff’s The Mummy character, Imhotep.

14. Pacific Rim was both Guillermo del Toro and Guillermo Navarro’s first experience shooting with digital cameras. Navarro bought seven Red Epic cameras specifically for the movie and used his own lenses, as he prefers shooting with his own camera equipment over renting it.

15. The movie takes place in 2013, 2020 and 2025.

16. Gipsy Danger is painted and detailed to resemble a World War II fighter plane. There is even nose art on its chest.

17. When asked why the pilots yell out to one another despite being telepathically linked, Travis Beacham said that doing so helps them stay focused.

18. The Jaegers are a staple of Japanese anime, where they’re often called mecha. Similar to many mecha anime series, Jaegers are controlled from within by human pilots, distinguishing them from other depictions of robots as automated, sentient or externally controlled.

19. Pacific Rim was the first Guillermo del Toro movie to feature Ron Perlman as a human character since Cronos.

20. Max Martini is 14 years older than Robert Kazinsky, who plays his son.

21. Ron Perlman kept the shoes he wore on Pacific Rim. Later on, his wife had them melted down and converted into a pair of heels for herself.

22. The character of Mako Mori is much younger than Stacker “Marshall” Pentecost, although in real life, Rinko Kikuchi is only 8 years younger than Idris Elba.

23. The set was built as a non-destroyed Hong Kong, then destroyed and redressed to play as a different area, post-monster battle. The Hong Kong set was used as four different streets and sets, with the placement and dressing of elements changed each time.

24. The title screen doesn’t appear until 17 minutes into the movie.

25. Stellan Skarsgard was considered for the role of Herc Hansen.

26. Striker Eureka, the white Australian Jaeger, was initially chosen to be the “Hero Jaeger” of the movie, but Guillermo del Toro thought that it’s appearance was “too cold” and “arrogant.”

27. Ron Perlman’s character, Hannibal Chau, could be named after James Hong’s character, Hannibal Crew, in Blade Runner, as Guillermo del Toro has named the movie as a huge inspiration for him as a director.