In what is being called "the worst massacre by a lone gunman in history," 32-year-old Anders Behring Breivik entered a Labor Party youth camp in Utoya, Norway, on Friday dressed as a police officer and opened fire on a group of teenagers. Breivik killed more than 84 people, most of them between the ages of 15 and 20, in what he believed was an attempt to stop "a deconstruction of Norwegian culture and mass-import of Muslims." Officials in Norway believe Breivik is also responsible for a bombing in Oslo several hours earlier, in which seven were killed and 15 wounded. After his arrest, officials unearthed Breivik's 1,500-page manifesto, 2083: A European Declaration of Independence, along with a chilling 12-minute video about his beliefs. He is currently awaiting trial.