CHEERS U.S. troops and civilians enjoy the USO holiday tour on Bagram Airfield, Afghanistan, Dec. 15, 2010. U.S. Navy Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, and his wife, Deborah, are hosting the tour. SHARE: Download: Full Size (0.07 MB) Credit: VIRIN: 106363-Y-JXF99-016.jpg Photo Gallery