OFFICIAL GREETING Deputy Defense Secretary Bob Work, left, exchanges greetings with Air Force Lt. Gen. Michael Dubie, deputy commander of U.S. Northern Command and vice commander of the U.S. element of the North American Aerospace Defense Command, upon arriving on Peterson Air Force Base, Colo., to meet with service members, April, 14, 2015. SHARE IMAGE: Download Image: Full Size (0.05 MB) Photo By: VIRIN: 345497-R-VZV01-499.jpg Photo Gallery