HOWITZER TOUR U.S. Defense Secretary Ash Carter shakes hands with crew members as he receives a tour of a static M109A6 self-propelled howitzer at the Grafenwoehr Training Area in Grafenwoehr, Germany, June 26, 2015. During his European trip, Carter also attended his first NATO ministerial in Brussels as defense secretary. SHARE: Download: Full Size (0.06 MB) Credit: VIRIN: 725492-Q-HGZ53-427.jpg Photo Gallery