ABC News'?? David Muir reported from Ground Zero,?? the hallowed site of the 9/11 terrorist attacks, as the nation learned of the death of Osama Bin Laden, the mastermind behind the attacks.
PHOTO: Alleged Sept. 11 attacks mastermind, Khalid Sheikh Mohammed, holds a piece of paper during a court recess at his Military Commissions pretrial hearing in the Guantanamo Bay U.S. Naval Base in Cuba, Oct. 15, 2012, in this photo of a sketch by courtr
PHOTO: In this photo of a sketch by courtroom artist Janet Hamlin and reviewed by the U.S. Department of Defense, Khalid Sheikh Mohammed reads a document during his military hearing at the Guantanamo Bay U.S. Naval Base in Cuba, Saturday, May 5, 2012.
PHOTO: FDNY Firefighters are shown in Times Square, after hearing the news that the 9-11 mastermind, Osama bin Laden, has been killed.
VIDEO: 9/11 mastermind led al Qaeda in killing scores of people around the world.
VIDEO: Military commission will try Khalid Sheikh Mohammed in Guantanamo Bay.