An American soldier walks ahead of an MKIV (Mark IV) British-made tank, circa 1918. (Photo by Hulton Archive/Getty Images)

A soldier eats ice cream as she visits a zoo in Pyongyang, North Korea, September 12, 2018. (Photo by Danish Siddiqui/Reuters)

American soldiers leaping from an armoured personnel carrier during exercises in Korea, 17th March 1954. (Photo by Three Lions)

A National Army of Colombia soldier, who was wounded by a mine, swims at a pool in Bello, municipality of Antioquia, March 25, 2015. (Photo by Fredy Builes/Reuters)

A soldier shares a tender moment with his girlfriend while other soldiers rest during a rehearsal of a military parade a few days before the Independence Day in Kiev, Ukraine, Monday, August 22, 2016. Ukraine to mark the 25th anniversary of the Independence Day on August 24. (Photo by Efrem Lukatsky/AP Photo)

A Saudi soldier fires a mortar towards Houthi movement position, at the Saudi border with Yemen April 21, 2015. (Photo by Reuters/Stringer)

Soldiers take part in a drill during a heavy snow in Heihe, Heilongjiang province, February 26, 2014. (Photo by Reuters/China Daily)

A line of soldiers firing handguns during a training session, circa 1920. (Photo by Keystone). P.S. All pictures are presented in high resolution.