Moment of Silence Defense Secretary Ash Carter and Marine Corps Gen. Joe Dunford, chairman of the Joint Chiefs of Staff, observe a moment of silence during a ceremony at the National 9/11 Pentagon Memorial marking the 15th anniversary of the 9/11 attacks, Sept. 11, 2016. DoD photo by Air Force Tech.Sgt. Brigitte N. Brantley SHARE: Download: Full Size (0.69 MB) Credit: Tech Sgt. Brigitte Brantley VIRIN: 160911-D-GO396-277.JPG Photo Gallery