U.S. Marines with 2nd Combat Engineer Battalion, Marine Air Ground Task Force-8 (MAGTF-8) fire a mine clearing line charge (MCLIC) for a Tank Mechanized Assault Course (TMAC) during Integrated Training Exercise (ITX) 5-17 at Marine Corps Air Ground Combat Center, Twentynine Palms, Calif., July 28, 2017. (Sgt. Kassie L. McDole/Marine Corps)
U.S. soldiers stand near and atop of an armored personal carrier, during a military drill at the army range, in Krivolak, central Macedonia, Monday, July 31, 2017. Some 300 troops with 120 vehicles of the 2nd Cavalry Regiment of the United States Army Europe (USAREUR) and nearly 100 troops from the Macedonian Army Engineer Battalion participated in the "Dragoon Guardian 17" military drill at the Krivolak army range in Macedonia. (Boris Grdanoski/AP)
Multiple B-25s simulate the Doolittle Raid on Tokyo at the Experimental Aircraft Association's AirVenture 2017 night show in Oshkosh, Wisc., July 26, 2017. (Scott M. Ash/Air Force)
A Indiana Patriot Guard rider salutes as the family of Navy Hospital Corpsman 2nd Class Ryan Lohrey drives by Thursday, July 27, 2017, in Indianapolis. Lohrey died July 10 along with 15 Marines when a military refueling plane crashed in Mississippi. (Darron Cummings/AP)
Marine Corps Lance Cpl. Benjamin C. Gasiewicz navigates past barbed wire during a training exercise at Marine Corps Air Ground Combat Center Twentynine Palms, Calif., July 21, 2017. (Cpl. Justin M. Smith/Marine Corps)
A soldier descends on a wall using the Australian rappel technique during a demonstration near Glen Jean, W.V., July 21, 2017. (Staff Sgt. Matt Britton/Army)
Survival, evasion, resistance and escape cadre instruct aircrew members from Travis Air Force Base, Calif., on basic water survival skills during a training session on July 19, 2017, in San Pablo Bay, Calif. (Louis Briscese/Air Force)
The crew of the Arleigh Burke-class guided-missile destroyer USS Rafael Peralta (DDG 115) mans the ship during its commissioning ceremony on July 29, 2017, at Naval Air Station North Island in San Diego, Calif. Rafael Peralta honors Marine Corps Sgt. Rafael Peralta, who was posthumously awarded the Navy Cross for actions during Operation Iraqi Freedom. (MC2 Zackary Alan Landers/Navy)
An LC-130 "Skibird" based out of Stratton Air National Guard Base in Scotia, N.Y., takes off from Greenland on July 28, 2017. Raven Camp is used to train aircrews on LC-130 operations on skiways. (Senior Master Sgt. Willie Gizara/National Guard)
