Competitors in the Big Air challenge at the Proryv-2016 festival of extreme sports in Moscow, Russia on March 27, 2016. (Photo by Xinhua/Rex Features/Shutterstock)

A Yemeni soldier, pictured through a vehicle's windscreen, which was damaged by a bullet, gestures out of the window, in Marib, Yemen October 15, 2015. Marib is a city that is heavily armed even by the standards of Yemen, where the ready availability of weapons helped start civil war and is now preventing anyone coming out on top. Yemenis often say there are three guns for every person, a boast that has become an urgent concern in a country where the United Nations says the humanitarian situation is "critical". (Photo by Angus McDowall/Reuters)

A woman tries a swing in front of a screen featuring New York scenes during the new Air France Exhibition called “Air France, France is in the Air” in New York June 25, 2014. (Photo by Timothy A. Clary/AFP Photo)

A high-kicking Parisian can-can dancer. (Photo by Hulton Archive/Getty Images). 1895

Back in England, one of the British soldiers that continue to return in their thousands from Northern France, belies any mood of defeat with some high spirited piping on a train. (Photo by Parker/Fox Photos/Getty Images). 1st June 1940

Jimmy Arnold, an overweight boy from Rochester, bites into a cake. (Photo by Reg Birkett/Keystone/Getty Images). 14th April 1951

An Aden civilian crouching in terror as British soldiers threaten him during Arabian demonstrations in Crater. (Photo by Express Newspapers/Getty Images). 1967

Film actress Audrey Hepburn (1929–1993) on a film set with her pet poodle, circa 1960. (Photo by Hulton Archive/Getty Images)