Watch HDToday. On September 11, 2001, the unimaginable transpired when devastating attacks on the World Trade Center forced the shutdown of the entire U.S. airspace. Thousands of kilometres away in Gander, Newfoundland, a group of Nav Canada air traffic controllers suddenly had the lives of 33,000 people in their hands and had to think fast to find a place for them to go. Discovery uncovers how these unsung heroes managed to safely land 224 planes in four hours, without incident.