Origin:

This meme comes from a song written by Clint Mansell for the movie "Requiem for a Dream". The track became immensly popular when it was re-arranged by Simone Benyacar, Daniel Nielsen, and Veigar Margeirsson for the 2002 film "Lord of the Rings:The Two Towers" and has been used in numerous movie trailers, often to a humorous result. Simply YouTube "Requiem for a Tower makes anything epic" and you will see an assortment of videos that use the song in a random movie trailer. It should be noted that this song, while epic, is overused.

Wikipedia: "Requiem for a Tower" is a version of Clint Mansell's Lux Æterna/Requiem For A Dream, re-orchestrated with a choir and full orchestra for a The Lord of the Rings: The Two Towers theatrical trailer. It was arranged by Simone Benyacar, Daniel Nielsen, and Veigar Margeirsson.

Although never intended for release, after considerable demand by fans the re-recording(s) were made available as part of the Requiem for a Tower album release from Corner Stone Cues^[2], a subsidiary catalogue of Howling Entertainment. While the release was originally made physically, production was discontinued indefinitely with increased digital sales of the album on major electronic music distributors iTunes & Amazon MP3

The popularity of this piece led to its use in popular culture outside the film, most notably in film and teaser trailers.