Considering how much it changed the face of blockbuster movies and the science fiction genre, it's bizarre to think "The Matrix" is turning 20 years old. Time to down the red pill and learn some interesting facts about the making of this modern classic.

1. The Wachowskis originally approached Will Smith in 1996 to star as Neo. Smith has since admitted he turned down the role because he didn't understand the script and opted to star in "Wild Wild West" instead.

2. In addition to Smith, the Wachowskis also approached Val Kilmer to play Morpheus.

3. The principal cast and crew members were required to read several philosophy books before seeing the screenplay, including Jean Baudrillard's "Simulacra and Simulation." That book can be seen on display in Thomas Anderson's apartment early in the film.

4. "The Matrix" wasn't officially greenlit by WB until well into pre-production. It was only after hiring artists Steve Skroce and comic book legend Geoff Darrow to storyboard the film and visualize the mind-bending action scenes that executives signed off on the project.

5. There's a reason Neo's fighting style in the first movie features far fewer kicking moves than in the sequels. Keanu Reeves was recovering from neck surgery during pre-production and didn't have full use of his legs.

6. Both Hugo Weaving and Carrie-Anne Moss were injured during filming. Moss refused to tell anyone about her ankle injury for fear of losing the role.

7. The scenes where Neo first wakes up from his captivity in The Matrix were filmed last, as Reeves had to loose approximately 15 pounds and shave his head to achieve the necessary emaciated look for his character.

8. Neo's criminal record folder lists his birthplace as being "Capital City, USA." While never overtly revealed in the films, the world simulated within the Matrix consists of a single, giant metropolis called Mega City.

9. Switch actress Belinda McCrory revealed that her character was originally intended to be played by a male actor in the real world and a female actress in the Matrix. This is one reason why the film has come to be viewed as an allegory for transgender identity.

10. Even Neo might have been a woman had things worked out differently. Reeves' "Speed" costar Sandra Bullock was approached to star in the film early on.

11. The Wachowskis cast numerous sets of twins as background extras for the "Woman in Red" sequence, as a subtle way of showing a computer program using recycled information.

12. "The Matrix" is often compared to 1998's "Dark City" in both story and visual style. As it turns out, many sets from "Dark City" were recycled for use in "The Matrix."

13. The main character in the DC Comics series "The Sandman" is also named Morpheus. The Wachowskis specifically instructed Laurence Fishburne to model his performance on that wise, inscrutable Morpheus.

14. This is the only film in the series where Neo uses guns.

15. "The Matrix" takes place over the course of 19 months. This is indicated by the timestamps of the phone traces seen in the beginning and end of the movie.