9/11: Days That Shocked the World: Season 1, Episode 2

1 - 2: Episode 2

Three hijacked aircraft had struck the iconic Twin Towers in New York and the Pentagon within less than an hour. But the nightmare was far from over. As the world watched in horror, the Twin Towers collapsed, and in western Pennsylvania a fourth hijacked airliner - United Flight 93 - crashed into a field. Rescue workers, survivors and witnesses remember the tragedy.