SECURITY CLASS Defense Secretary Robert M. Gates talks with Air Force Academy cadets while teaching a national security class as part of the Capstone Seminar at the Air Force Academy in Colorado Springs, Colo., March 4, 2011. Later, Gates addressed all the cadets in a speech that marked his last visit to the academy. SHARE: Download: Full Size (0.06 MB) Credit: VIRIN: 368968-U-YIH33-127.jpg Photo Gallery