Passenger attempts to overcome aircraft hijackers on 11 September are the focus of a US documentary to be broadcast on the fourth anniversary of the attacks.
United Airlines flight 93 crashed in Shanksville, Pennsylvania
The Flight That Fought Back examines the fourth hijacked plane, believed to have been aimed at the White House.
As passengers tried to overcome hijackers the Boeing 757 crashed into a field, killing all 41 people on board.
Using actors to recreate scenes from the hijack, the two-hour show will be broadcast in the US on 11 September.
Executive producer Phil Craig said his team pieced the story together through interviews with family members who spoke to the passengers in the hour before the crash.
Eyewitnesses who saw United Airlines flight 93 crash into the field in Shanksville, Pennsylvania, were also used, along with other documentary evidence.
Only family members were allowed to hear the plane's cockpit voice recorder, which America's 9/11 Commission said proved hijackers deliberately crashed the plane as passengers were about to reach the cockpit.
"Forty strangers from across the world banded together and took an action which helped to save this whole country from a further disaster," said Discovery Channel general manager Jane Root.
America's National Geographic channel has scheduled a four-hour documentary into the cause of the 11 September attack for this autumn and ABC network has planned a mini series on the subject for 2006.
Earlier this month Platoon director Oliver Stone announced he would direct a film starring Nicolas Cage as one of two police officers trapped in rubble after the 11 September attacks.