President Barack Obama, U.S. Defense Secretary Chuck Hagel, and the Chairman of the Joint Chiefs of Staff Gen. Martin E. Dempsey participate in the 9/11 memorial ceremony at the Pentagon in Washington, Sept. 11, 2014. The observance was held in the National 9/11 Pentagon Memorial and included a moment of silence and reflection for those who were lost Sept. 11, 2001. (Coast Guard photo by Petty Officer 2nd Class Patrick Kelley/Released)