Remembering the 40 heroes who were aboard Flight 93 on 9/11

Since 2001, a great deal of attention has been paid to the Sept. 11 attacks on the World Trade Center and The Pentagon. But less so for Flight 93. The U.S. Capitol was the likely target of where hijackers had planned to crash the plane. Instead, passengers and crew forced the plane down in Shanksville, Pennsylvania — now an important touchstone site in the community. William Brangham reports.