unsafe and much CGI work was done to create the jungle action sequence. Visual effects supervisor Pablo Helman (who worked on Lucas's Star Wars: Episode I – The Phantom Menace and Star Wars: Episode II – Attack of the Clones as well as Spielberg's War of the Worlds and Munich) traveled to Brazil and Argentina to photograph elements that were composited into the final images. Industrial Light and Magic then effectively created a virtual jungle with a geography like the real Amazon. The appearance of a live alien and flying saucer was in flux. Spielberg wanted the alien to resemble a Grey alien, and also rejected early versions of the saucer that looked "too Close Encounters". Art director Christian Alzmann said the esthetic was "looking at a lot of older B-movie designs—but trying to make that look more real and gritty to fit in with the Indy universe." Other reference for the visual effects work included government tapes of nuclear tests, and video reference of real prairie dogs shot in 1080p by Nathan Edward Denning. Music John Williams began composing the score in October 2007; 10 days of recording sessions wrapped on March 6, 2008, at Sony Pictures Studios. Williams described composing for the Indiana Jones universe again as "like sitting down and finishing a letter that you started 25 years ago". He reused Indiana's theme (The Raiders March) and also Marion's from Raiders of the Lost Ark, and also composed five new motifs for Mutt, Spalko and the skull. Williams gave Mutt's a swashbuckling feel, and homaged film noir and 1950s B-movies for Spalko and the crystal skull respectively. The movie's first scene is accompanied by Elvis Presley's 1956 version of "Hound Dog", arguably the biggest hit of the movie's era, and an RIAA-certified 4× Platinum recording. As an in-joke, Williams incorporated a measure and a half of Johannes Brahms' "Academic Festival Overture" when Indiana and Mutt crash into the library. The soundtrack features a Continuum, an instrument often used for sound effects instead of music. The Concord Music Group released the soundtrack on May 20, 2008. Release The Kingdom of the Crystal Skull premiered at the Cannes Film Festival on May 18, 2008, a couple of days ahead of its worldwide May 21–23 release. It was the first Spielberg film since 1982's E.T. the Extra-Terrestrial to premiere at Cannes. The film was released in approximately 4,000 theaters in