A U.S. Marine fires a M27 Infantry Automatic Rifle during a live fire exercise aboard amphibious assault ship USS America (LHA 6), Oct. 3. - A U.S. Marine fires a M27 Infantry Automatic Rifle during a live fire exercise aboard amphibious assault ship USS America (LHA 6), Oct. 3.

U.S. Marines run up stairs during a stair walk at the San Diego Convention Center, San Diego, Sept. 11. - U.S. Marines run up stairs during a stair walk at the San Diego Convention Center, San Diego, Sept. 11.

A U.S. Marine with the Marine Corps Shooting Team fires at a target while in the prone position Sept. 14, 2016, at Altcar Training Camp, Merseyside, England. The Marines are competing in the Royal Marines Operational Shooting Competition, from September 6-22, 2016. The U.S. Marines are competing against the Royal Netherlands Marine Corps and the Royal Marines. The U.S. Marine is with Weapons Training Battalion, Marine Corps Base Quantico, Virginia. - A U.S. Marine with the Marine Corps Shooting Team fires at a target while in the prone position Sept. 14, 2016, at Altcar Training Camp, Merseyside, England. The Marines are competing in the Royal Marines Operational Shooting Competition, from September 6-22, 2016. The U.S. Marines are competing against the Royal Netherlands Marine Corps and the Royal Marines. The U.S. Marine is with Weapons Training Battalion, Marine Corps Base Quantico, Virginia.

The F-35B made its first trans-Atlantic flight June 29, 2016. Three F-35’s flew from Marine Corps Air Station Beaufort in South Carolina and landed at Royal Air Force Base Fairford in Gloucestershire, England. They were assisted by two KC-10’s, and refueled 15 times over the Atlantic. (U.S. Marine Corps photo by Cpl. Brian Burdett/Released) - The F-35B made its first trans-Atlantic flight June 29, 2016. Three F-35’s flew from Marine Corps Air Station Beaufort in South Carolina and landed at Royal Air Force Base Fairford in Gloucestershire, England. They were assisted by two KC-10’s, and refueled 15 times over the Atlantic. (U.S. Marine Corps photo by Cpl. Brian Burdett/Released)

An international Corps of Marines from Sweden, Finland, and the U.K. conduct amphibious assaults on a beachhead in Ravlunda, Sweden, for local media outlets during BALTOPS 2015, June 13. The amphibious forces are part of 17 NATO Allies and partner nations that are integrated in air, land, and sea operations to improve their combined-force capability to work together and to respond to threats in the Baltic region. - An international Corps of Marines from Sweden, Finland, and the U.K. conduct amphibious assaults on a beachhead in Ravlunda, Sweden, for local media outlets during BALTOPS 2015, June 13. The amphibious forces are part of 17 NATO Allies and partner nations that are integrated in air, land, and sea operations to improve their combined-force capability to work together and to respond to threats in the Baltic region.