Greeting Line Army Command Sgt. Maj. John W. Troxell, senior enlisted advisor to the chairman of the Joint Chiefs of Staff, meets with airmen at al Dhafra Air Base, United Arab Emirates, Dec. 23, 2017, during the 2017 USO Holiday Tour. DoD photo by Navy Petty Officer 1st Class Dominique A. Pineiro SHARE: Download: Full Size (0.9 MB) Credit: Dominique A. Pineiro VIRIN: 171223-D-PB383-001.JPG Photo Gallery