Image 0 of 5As seen through a night-vision device, Marines conduct clearing procedures for a building as part of Combined Composite Training Unit Exercise at Fort Jackson, Ga., Dec. 4, 2017. The Marines are assigned to Battalion Landing Team, 2nd Battalion, 6th Marine Regiment, 26th Marine Expeditionary Unit. (Lance Cpl. Tojyea G. Matally/Marine Corps) A Marine assigned to the 3rd Reconnaissance Battalion supervises another Marine carrying a rifle during the water tread portion of a screening for a basic reconnaissance course at Camp Hansen in Okinawa, Japan, Dec. 1, 2017. (Cpl. Breanna L. Weisenberger/Marine Corps) Airmen prepare a C-130J Super Hercules cargo aircraft in east Africa, Dec. 3, 2017. The airmen are supporting a mission to promote security in East Africa. (Staff Sgt. Gustavo Castillo/Air Force) A Navy Super Hornet receives fuel from an Air Force KC-135 Stratotanker over Afghanistan, Dec. 7, 2017. Navy Super Hornets conducted a series of precision airstrikes against six Taliban narcotic targets in Helmand province. (Jeff Parkinson/Air Force ) Sailors fold an American flag during a double interment as part of a ceremony at Joint Base Pearl Harbor-Hickam, Hawaii, Dec. 6, 2017, to mark the attacks on Pearl Harbor and Oahu. (Randi Brown/Navy)