It's been almost 12 years since the 9/11 attacks, which presents the US military with an unusual concern: Many of its guards at Guantanamo Bay were just kids when the attacks happened. To make sure they fully grasp the seriousness of their duties, the military conducts briefings—or "history lessons" in the words of ProPublica—on the attacks. They consist of a 17-slide PowerPoint presentation that includes information on the hijackers, photos of the destruction, and 9-1-1 calls from the towers.
ProPublica got eight of the pages in a Freedom of Information Act request (none have anything more than routine info), and the FBI held back the other nine over security concerns. Of the 166 detainees at Gitmo, five are currently on trial for allegedly helping plot the 9/11 attacks. ProPublica made the FOIA request after seeing a mention of the briefings in the Huffington Post, which says they "left many participants in tears." Click to see the slides as part of ProPublica's full article. (More 9/11 attacks stories.)