United Airlines Flight 93 crashed in a field outside the small town of Shanksville after being hijacked by four men as part of the September 11, 2001 attacks. During the flight several passengers and crew members made telephone calls, through which they learned about the attacks on the World Trade Center and the Pentagon. As a result, the passengers decided to mount an assault against the hijackers.
The plane later crashed killing all 44 people aboard, including the hijackers.
Analysis of the plane’s flight recorders has revealed how the actions taken by the passengers that day prevented the aircraft from reaching its intended destination: either the White House or the United States Capitol. 
I will be returning to the site on September 11, 2008 to photograph the 7th anniversary of the event, along with a visit from presidential candidate John McCain.
“Never Forget: We honor those who saw their untimely fate before them and chose to defeat evil to ensure America’s freedom. FLIGHT 93.”