A Tragedy of Errors. On Feb. 21, 2010, a convoy of vehicles carrying civilians headed down a mountain in central Afghanistan and American eyes in the sky were watching. "The Americans were using some of the most sophisticated tools in the history of war, technological marvels of surveillance and intelligence gathering that allowed them to see into once-inaccessible corners of the battlefield. But the high-tech wizardry would fail in its most elemental purpose: to tell the difference between friend and foe." FOIA-obtained transcripts of US cockpit and radio conversations and an interactive feature provide a more in-depth understanding of what happened.