Fighters of the pro-government Popular Resistance Committees militia carry a cannon as they transport it in parts to Yemen's southwestern war-torn city of Taiz December 26, 2015. (Photo by Reuters/Stringer)

A bloodied man who carried dead and wounded, speaks on the phone at the site of a suicide attack an explosion that struck a protest march, in Kabul, Afghanistan, Saturday, July 23, 2016. Witnesses in Kabul say that an explosion causing multiple casualties struck the march by members of Afghanistan’s largely Shiite Hazara ethnic minority group, who were demanding that a major regional electric power line be routed through their impoverished home province. (Photo by Omar Sobhani/Reuters)

These beautiful shots may look like works of modern art – but they are actually close-ups of chemical reactions. The works were snapped with the help of a group of scientists from the University of Science and Technology of China (USTC) in Anhui, China. Here: Zinc reacting with lead nitrate in a soft gel to form lead crystals. (Photo by Yan Liang/Caters News)

North Korean leader Kim Jong Un (front) stands on the conning tower of a submarine during his inspection of the Korean People's Army (KPA) Naval Unit 167 in this undated photo released by North Korea's Korean Central News Agency (KCNA) in Pyongyang June 16, 2014. (Photo by Reuters/KCNA)

A farrier attaches a horse shoe still hot from the furnace at The Household Cavalry Mounted Regiment (HCMR) at Hyde Park Barracks on March 28, 2012 in London, England. (Photo by Peter Macdiarmid/Getty Images)

Tech. Sgt. Milo Hinson, 3rd Combat Camera Squadron, uses a flashlight while shooting a Berretta 9mm during the night-fire portion of Advance Weapons, Tactics and Techniques training in San Antonio. During night-fire training, airmen learn how to tactically illuminate targets with flashlights and practice using night vision goggles. (Photo by Staff Sgt. Jonathan Snyder/U.S. Air Force). 2011

The crowd is reflected in the glasses of a bearded competitor at the third annual National Beard and Moustache Championships in Las Vegas, Nevada on November 11, 2012. (Photo by Frederic J. Brown/AFP Photo)

Ernie Lotinga, looking terrified as a gun is pointed in his face, in a scene from the play “My Wife's Family”, at the Garrick Theatre, London. (Photo by Sasha/Getty Images). 24th February 1941