Oct. 2 (Bloomberg) -- On December 14, 2012 the world watched in horror as a single gunman shot and killed 20 children and 6 teachers at Sandy Hook Elementary. As the country grasped for ways to prevent another school shooting, a contractor specializing in armoring vehicles in Afghanistan and Iraq came up with one solution: armoring schools with a bulletproof whiteboard. Video by Alyssa Zahler, Amy Marino. (Source: Bloomberg)