A woman looks at a swimmer getting herself warm after the annual Christmas winter swimming competition in the Vltava river in Prague December 26, 2014. (Photo by David W. Cerny/Reuters)

A woman greets a street artist at the San Fermin festival in Pamplona, northern Spain July 8, 2016. (Photo by Eloy Alonso/Reuters)

A woman photographs “Super Space Titan Kitty” by Colin Christian at the “Hello! Exploring the Supercute World of Hello Kitty” museum exhibit in honor of Hello Kitty's 40th anniversary, at the Japanese American National Museum in Los Angeles, California October 10, 2014. (Photo by Lucy Nicholson/Reuters)

Miniature spring-wound 35-mm film camera in a modified cigarette pack. The Tessina’s small size and quiet operation provided more options for concealment than most commercially available models. (Photo by Central Intelligence Agency)

An injured girl reacts at a site hit by an airstrike in the rebel-held Douma neighbourhood of Damascus, Syria November 7, 2016. (Photo by Bassam Khabieh/Reuters)

Flames from the Erskine Fire engulf a trailer near Weldon, California, U.S. June 24, 2016. (Photo by Noah Berger/Reuters)

“Weapons Instructor”, 2012. It’s a well known fact that the IDF trains some of the best soldiers in the world, but at the source of every good soldier lies an exceptional instructor – and that’s where Cpl. Daniella Stepanoe steps in. She travels from base to base training everyone from paratroopers to elite special forces units in the use of their weapons. (Photo by Israel Defense Forces)

Street fighting in Berlin between Government troops and Spartacists, during the Spartacist uprising which followed Germany's defeat in World War I. (Photo by Keystone/Getty Images). 1919