A Marine Corps KC-130J Hercules aircraft with Marine Aerial Refueler Transport Squadron (VMGR) 352, conducts division tactical navigation training with VMGR-152 as part of unit-level training Evergreen at Naval Air Station Whidbey Island, Wash., Aug. 18, 2017. (Cpl. Joseph Abrego/Marine Corps)
Secretary of Defense Jim Mattis talks with U.S. Army Lt. Gen. Stephen Townsend, the commander of Combined Joint Task Force Operation Inherent Resolve, during a flight in Baghdad, Iraq, Aug. 22, 2017. (Air Force Staff Sgt. Jette Carr/DoD)
A U.S. Air Force Aerial Demonstration Squadron "Thunderbird" F-16 sits on the flight line at sunrise on Atlantic City Air National Guard Base, N.J., Aug. 23, 2017. The Thunderbirds are in town for the Thunder Over the Boardwalk Air Show which takes place over the beaches of Atlantic City, N.J., Aug. 22-23. (Master Sgt. Matt Hecht/Air National Guard)
Soldiers of 3rd Armored Brigade Combat Team, 4th Infantry Division, Fort Carson, Colo., deploy the Joint Assault Bridge System while conducting a dry gap crossing during Exercise Combined Resolve IX at the Grafenwoehr Training Area, Germany, Aug. 23 2017. (Pfc. Zachery Perkins/Army)
Airmen assigned to the South Carolina Air National Guard view the solar eclipse at McEntire Joint National Guard Base, S.C., Aug. 21, 2017. (Tech. Sgt. Nicole Szews/Air National Guard)
Chief petty officer selectees march through Boston during Chief Petty Officer Heritage Week on Aug. 22, 2017. The heritage week is a week dedicated to mentoring the Navy's newest chiefs through naval history and heritage training aboard USS Constitution. (Gunners Mate 2nd Class Erin Bullock/Navy)
Airmen play football after their duty day at Young Air Assault Strip, Fort McCoy, Wis., Aug. 22, 2017, during exercise Patriot Warrior. (Staff Sgt. Corban Lundborg/Air Force)
U.S. Marine Cpl. Nicolas Villanueva, right, motor transportation operator, Combat Logistics Detachment, Marine Rotational Force Darwin, works with soldiers from the Chinese People's Liberation Army to build a hut on Aug. 23, 2017, during Indigenous Australian culture classes for Exercise Kowari 2017 in Cairns, Australia. (Sgt. Emmanuel Ramos/Marine Corps)
Sgt. Antonio Hernandez, 173rd Airborne Infantry Brigade Combat Team, completes the grenade range lane on Aug. 22, 2017, during U.S. Army Europe's 2017 European Best Warrior Competition. (Master Sgt. Crista Mary Mack/Army)
A family waves at the the Nimitz-class aircraft carrier USS George H.W. Bush (CVN 77) as the ship arrives at Naval Station Mayport, Fla., Aug. 19, 2017. (MC2 Timothy Schumaker/Navy)