Remembering History: Unforgettable 9/11 Images Unforgettable 9/11 Images Officials examine the crater Sept. 11, 2001 at the crash site of United Airlines Flight 93 in Shanksville, Pennsylvania.

Unforgettable 9/11 Images Unforgettable 9/11 Images Officials examine the crater Sept. 11, 2001 at the crash site of United Airlines Flight 93 in Shanksville, Pennsylvania.

Unforgettable 9/11 Images Unforgettable 9/11 Images Officials examine the crater Sept. 11, 2001 at the crash site of United Airlines Flight 93 in Shanksville, Pennsylvania.