- "A hero need not speak. When he is gone, the world will speak for him."
- —Magazine Ad
Believe is a Microsoft marketing campaign for Halo 3 produced by New Deal Studios. It features the word "Believe" as a tagline, and appears to be honoring the legacy of SPARTAN-117, citing him as a hero of the United Nations Space Command whose brave actions inspired other servicemen during the Human-Covenant War.
It includes handouts, live-action TV commercials, magazine page advertisements, and XBOX live marketplace ads:
- Believe - A pamphlet distributed at the Project Revolution musical festival, featuring in-universe musical presentation of the UNSC Symphony Orchestra.
- Diorama - An interactive flash movie, a part of the Believe campaign for Halo 3. It is a fly through of the John-117 Monument, and can be viewed at the Halo 3 website.
- Museum - A live-action TV commercial featuring Retired Major Pawel Czernek, a UNSC veteran that fought in the Battle of New Mombasa alongside SPARTAN-117, reminiscing of his memories of the inspiring hero.
- Hunted - A live-action TV commercial.
- Enemy Weapon - A live-action TV commercial.
- Gravesite - A live-action TV commercial that explores the battleground and talks of Spartan 117's "death".
- Believe: The John 117 Monument - A live-action online video, describing the in-universe construction of the memorial diorama.
- The creators of the campaign were not informed of the story of Halo 3, leading to multiple inconsistencies with the story depicted in Believe, and the game's story. Due to this, no aspect of the marketing campaign can be considered canon.
- Because the events that were depicted in the interviews (the Second Battle of Mombasa and the capture and death of the Master Chief) conflict with events as they transpired in Halo 3, the interviews may alternatively be a massive cover-up operation performed by ONI Section Two to cover up the truth about the Forerunners, the Halo Array, and the Flood.
- On Xbox.com, there is a collection of photographs from war photographer Jake Courage titled "Shooting a Hero".
- Stan Winston Studio was responsible for the diorama featured in the Halo 3 Believe ads.
- The melody that was used in the Believe commercials was created by Polish pianist Frédéric Chopin and is called "Preludes #15, Raindrop".
- In the Halo 3: ODST campaign levels Mombasa Streets and Tayari Plaza, there are several graffiti where the player can read BELIEVE, a reference to the marketing campaign for Halo 3 of the same name.
- A new trailer released for the game Serious Sam HD entitled "Seriously Believe" is an obvious tribute or parody to the Believe campaign, utilizing a selection of frozen in-game views in place of the models, a similar track, and a black screen at the end with the words "Seriously Believe" appearing, very similar to the original "Believe" trailer.
- The "Believe" advertisement trailer was named one of the best television advertisements of the decade by AdWeek in 2010. The same trailer was named number 59 on Gametrailers list of the 'Top 100 Trailers of All Time' in 2011.