James Cameron originally planned to have the film completed for release in 1999. At the time, the special effects he wanted increased the budget to $400 million. No studio would fund the film, and it was shelved for almost 10 years.

An early casting call for the female lead was posted, identifying the movie as James Cameron's “Battle Angel.”

James Cameron's go-to action guy, Michael Biehn, who starred in Cameron's “The Terminator,” “Aliens” and “The Abyss” — was considered for the role of the tough-nut Col. Miles Quaritch. Cameron ultimately had to pass because he'd already cast Sigourney Weaver (who starred opposite Biehn in “Aliens”) and he didn't want people to think it was “Aliens” all over again. The role eventually went to Stephen Lang.

Sigourney Weaver says, as Dr. Grace Augustine, she was channeling James Cameron. “I teased him because to me, I'm playing Jim Cameron in the movie as this kind of brilliant, approach-driven, idealistic perfectionist. But that same somebody has a great heart underneath.”

The movie is 40 percent live action and 60 percent photo-realistic CGI. Most of the motion capture technology was used for the CGI scenes.

James Cameron was convinced that CGI effects had progressed enough to make this film when he saw Gollum in “The Lord of the Rings: The Two Towers.”

Matt Damon and Jake Gyllenhaal were some of the actors considered for the role of Jake Sully, but James Cameron decided to cast the then unknown Sam Worthington in the lead.

According to Sam Worthington, he was invited to the casting via a phone call. He didn't know anything about the script, nor was he told the director's name. Sam was initially disappointed, thinking it was “another waste of time.”

Interestingly, Sam Worthington appeared in last year's “Terminator Salvation,” the same franchise created by James Cameron in 1984 with “The Terminator.”

In much of the movie, Sigourney Weaver's avatar wears a Stanford tank top. Weaver attended Stanford in the early 1970s.

As a sort of Na'vi/Pandora boot camp, director James Cameron took the cast and crew to Hawaii, where they spent their days trekking through the forests and jungles and living off the land (building campfires, eating fish, etc.). After these intensive hikes, however, they spent their nights at a Four Seasons hotel.

Zoe Saldana trained non-stop for six months to prepare for her role as Neytiri in “Avatar,” including martial arts, archery and horseback riding. Zoe even dressed up as a warrior during some of the training, complete with a Na'vi tail, to see how it felt. She says she's a sci-fi geek who just happens to dress nice.

The Na'vi language was created entirely from scratch by linguist Paul R. Frommer. James Cameron hired him to construct a language that the actors could pronounce, but did not resemble any single human language. Frommer created about 1,000 words.

“Avatar” is the highest-grossing film of all time, bringing in $700 million domestically. James Cameron's previous film “Titanic” was the first film to gross $500 and $600 million domestically.

James Cameron wrote a screenplay for “Spider-Man” but was turned down by the studios, with his version being deemed “too violent.” Sam Raimi's version got the green light instead.