President Barack Obama, left, Defense Secretary Chuck Hagel, center, and Army Gen. Martin Dempsey, chairman of the Joint Chiefs, salute the American flag as the national anthem plays during a 9/11 ceremony at the Pentagon Memorial, Sept. 11, 2014. President Barack Obama, left, Defense Secretary Chuck Hagel, center, and Army Gen. Martin Dempsey, chairman of the Joint Chiefs, salute the American flag as the national anthem plays during a 9/11 ceremony at the Pentagon Memorial, Sept. 11, 2014. SHARE: Download: Full Size (1.11 MB) Tags: Photo Essays Credit: VIRIN: 207492-H-SZF79-718.jpg Photo Gallery