Secretary of Defense Leon E. Panetta, center, introduces U.S. Air Force Gen. Mark A. Welsh III, right, the chief of staff of the Air Force, to 2012 U.S. Paralympic Team member Kari Miller as Paralympic athletes visit the Pentagon Sept. 13, 2012. The Paralympics is a major international sporting event in which thousands of athletes, including wounded and injured U.S. Service members, participate in a variety of sporting events.