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

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

A German special anti-tank gun is ready to fire during the army maneuvers in Silesia, Poland, on September 22, 1928. (Photo by AP Photo)

Iraqi troops fire artillery towards Islamic State (IS) group jihadists' positions in west Mosul on March 11, 2017 during the ongoing battle to retake the city from the group. (Photo by Aris Messinis/AFP Photo)

Fireplace for children, Trondheim, Norway, by Haugen/Zohar. The children of Trondheim come to sit around the fire and tell stories in this whimsical cone hut, made with materials recycled from a construction site. (Photo by Jason Havneraas/The Guardian)

Libyan forces allied with the U.N.-backed government fire weapons during a battle with IS fighters in Sirte, Libya, July 21, 2016. (Photo by Goran Tomasevic/Reuters)

A woman attempts to cover a tear gas canister fired by police at a crowd in Srinagar protesting against the recent killings in Kashmir, August 17, 2016. (Photo by Cathal McNaughton/Reuters)