Three Chinese soldiers at the time of a civil war in China. (Photo by General Photographic Agency/Getty Images). 1922

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

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

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

U.S Army combat camera photographer Spc. Hilda Clayton took this photo July 2, 2013 that was released by the U.S. Army, that shows an Afghan soldier engulfed in flame as a mortar tube explodes during an Afghan National Army live-fire training exercise in Laghman Province, Afghanistan. The accident killed Clayton and four Afghan National Army soldiers. (Photo by Spc. Hilda Clayton/U.S. Army via AP Photo)

A close-up shot of dews of a soldier fly on August 2014, in Banten, Indonesia. Wildlife photographer takes incredible close-up images of tiny bugs. Yudy Sauw has captured close-up images of creepy crawlies – revealing their disturbing faces. The insects have an assortment bulging eyes and sharp pincers and look grotesque in the face-to-face shots. The miniature-models include a soldier fly, a red ant and a longhorn beetle. The 33-year-old photographed the bugs at his home studio in Banten, Indonesia, placing them 2-10 centimeters away from the camera. (Photo by Yudy Sauw/Barcroft Media)

An Israeli soldier of the Caracal battalion smiles during a 23-kilometer march marking the end of their training in Israel's Negev desert, near Kibbutz Sde Boker February 14, 2013. The “Caracal” battalion, two-thirds of whose members are women, was established in 2004 with the purpose of incorporating female soldiers in combat units. The main mission of Caracal is routine patrols on Israel's border with Egypt to intercept infiltrators and smuggling from the Sinai desert. (Photo by Darren Whiteside/Reuters)

Displaced Sunni people, who fled the violence in the city of Ramadi, arrive at the outskirts of Baghdad, April 17, 2015. Iraqi security forces fought Islamic State militants at the gates of the western city of Ramadi on Friday, and local authorities warned it was in danger of falling unless reinforcements arrived soon. (Photo by Reuters/Stringer)