The Dark Knight is a 2008 superhero film directed and co-written by Christopher Nolan. Based on the DC Comics character Batman, the film is part of Nolan's Batman film series and a sequel to 2005's Batman Begins. Christian Bale reprises the lead role. The film follows Bruce Wayne/Batman (Bale), District Attorney Harvey Dent (Aaron Eckhart), Assistant D.A. Rachel Dawes (Maggie Gyllenhaal), and Police Commissioner James Gordon (Gary Oldman) and their struggles and journey in combating the new threat of the Joker (Heath Ledger). The Joker's identity is left a mystery in the film, while Dent's transformation from heroic district attorney to disfigured killer Two-Face is presented entirely. Nolan's inspiration for the film was the Joker's comic book debut in 1940, and the 1996 series The Long Halloween, which retold Two-Face's origin. The Dark Knight was filmed primarily in Chicago, as well as in several other locations in the United States, the United Kingdom, and Hong Kong. Nolan used an IMAX camera to film some sequences, including the Joker's first appearance in the film.
On January 22, 2008, after he had completed filming The Dark Knight, Heath Ledger died from a toxic combination of prescription drugs, leading to intense attention from the press and moviegoing public. Warner Bros. initially created a viral marketing campaign for The Dark Knight, developing promotional websites and trailers highlighting screen shots of Ledger as the Joker, but after Ledger's death, the studio refocused its promotional campaign. The film was released on July 16, 2008 in Australia, on July 18, 2008 in North America, and on July 24, 2008 in the United Kingdom. Before its box office debut in North America, record numbers of advance tickets were sold for The Dark Knight. It was greeted with positive reviews upon release, and became only the second film to earn more than $500 million at the United States box office, setting numerous other records in the process. It is also the fourth highest grossing film worldwide. Following its critical and commericial success, The Dark Knight has gone to garner multiple awards recognizing Ledger's performance as well as the movie as one of the best of 2008.