What's the name of the song played in Halo 3's Believe trailer?

[tee]

The trailer is the one showing inanimate figures of marines, brutes, etc, ending with Master Chief activating a plasma grenade and raising his head.

 

[Ladyoasis]

The video, titled "Believe", featured the same diorama, with the camera sweeping over it accompanied by a single piano melody, an excerpt from Frédéric Chopin's Raindrop Prelude (Op. 28, Prelude No. 15 in D-flat major), to reveal an apparently defeated Master Chief being held in the air by a Brute in the middle of the battle depicted in the diorama, in a frozen moment in time. The Master Chief then animates briefly, as a grenade (referred to in the previous video) activated in his hand, and raised his head to look into the camera. After the scene faded to black, it ended with the words: "BELIEVE IN A HERO". It should be noted that this scene does not appear in the game itself.[23]

 

[Ladyoasis]

The video, titled "Believe", featured the same diorama, with the camera sweeping over it accompanied by a single piano melody, an excerpt from Frédéric Chopin's Raindrop Prelude (Op. 28, Prelude No. 15 in D-flat major), to reveal an apparently defeated Master Chief being held in the air by a Brute in the middle of the battle depicted in the diorama, in a frozen moment in time. The Master Chief then animates briefly, as a grenade (referred to in the previous video) activated in his hand, and raised his head to look into the camera. After the scene faded to black, it ended with the words: "BELIEVE IN A HERO". It should be noted that this scene does not appear in the game itself.[23]