Col. Jay Flournoy speaks to a crowd of more than 400 family, friends and retirees, at the 10th anniversary 9/11 retreat and remembrance ceremony on Sept. 11, 2011, at Travis Air Force Base, Calif. In 2001, Flournoy was a major on duty at the Pentagon who heard and felt the concussion when American Airlines Flight 77 crashed into the building, killing all 59 on board and 125 on duty at the Pentagon. "I urge you, as painful as it may be, to do whatever is necessary to ensure that you and your loved ones never forget that September day," he said. (U.S. Air Force Photo/Senior Master Sgt. Ellen Hatfield)