"Lux Aeterna" (pronounced [lʊks ɛtɛrna]; Latin for "eternal light") is a composition by Clint Mansell, the leitmotif of a movie from 2000, Requiem for a Dream, and the penultimate piece in the Requiem for a Dream score. The popularity of this piece led to its use in popular culture outside the film, most notably in film and teaser trailers, such as Sunshine, and multiple remixes and remakes by other producers. It was also used in the Top Gear: Polar Special episode.
A version of the track was re-orchestrated with a choir and full orchestra for The Lord of the Rings: The Two Towers trailer. It was arranged by Simone Benyacar, Daniel Nielsen, and Veigar Margeirsson.
The orchestrated version was made available as part of the Requiem for a Tower album release from Corner Stone Cues.