Believe

"A hero is more than a person, a hero is a belief. A belief that, against impossible odds, the world can be saved—and that the world is still worth saving. Heroes inspire that belief in us. They renew our faith and give us that most precious of all gifts—hope. The world needs heroes. That's why, when a true hero arrives, the world will honor him."

— Xbox.com introduction to "Believe"

Believe is a Microsoft marketing campaign for Halo 3.

It features the word "Believe" as a tagline, and appears to be honoring the legacy of SPARTAN-117, citing himself as a hero of the United Nations Space Command Defense Force whose brave actions inspired other servicemen during the Human-Covenant War.

It includes handouts, live-action TV commercials, and magazine page advertisements:

• Believe (Magazine) - An advertisement in the September issue of EGM.
• Believe (Event) - A pamphlet distributed at the Projekt Revolution musical festival, featuring in-universe musical presentation of the UNSC Symphony Orchestra
• Museum - A live-action TV commercial featuring Pawel Czernek, a UNSC veteran that fought in the Battle of New Mombasa alongside SPARTAN-117, reminiscing of his memories of the inspiring hero
• Believe Ad - The follow up to Museum.
• Diorama - A live-action TV commercial featuring the John-117 Monument, a diorama of a battle between the UNSC and Covenant Loyalists, on display at the Museum of Humanity created in 2607