Avatar is a 2009 American epic science fiction film written and directed by James Cameron, and starring Sam Worthington, Zoe Saldana, Stephen Lang, Michelle Rodriguez, Joel David Moore, Giovanni Ribisi and Sigourney Weaver. The film is set in the mid-22nd century, when humans are mining a precious mineral called unobtanium on Pandora, a lush habitable moon of a gas giant in the Alpha Centauri star system. The expansion of the mining colony threatens the continued existence of a local tribe of Na'vi – a humanoid species indigenous to Pandora. The film's title refers to a genetically engineered Na'vi body with the mind of a remotely located human, and is used to interact with the natives of Pandora.
Development of Avatar began in 1994, when Cameron wrote an 80-page treatment for the film. Filming was supposed to take place after the completion of Cameron's 1997 film Titanic, for a planned release in 1999, but according to Cameron, the necessary technology was not yet available to achieve his vision of the film. Work on the language of the film's extraterrestrial beings began in summer 2005, and Cameron began developing the screenplay and fictional universe in early 2006. Avatar was officially budgeted at $237 million. Other estimates put the cost between $280 million and $310 million for production and at $150 million for promotion. The film made extensive use of cutting edge motion capture filming techniques, and was released for traditional viewing, 3D viewing (using the RealD 3D, Dolby 3D, XpanD 3D, and IMAX 3D formats), and for "4D" experiences in select South Korean theaters. The stereoscopic filmmaking was touted as a breakthrough in cinematic technology.