Battle-weary American troops withdraw from Yong San in Korea. (Photo by Keystone/Getty Images). 1950

American soldiers leaping from an armoured personnel carrier during exercises in Korea, 17th March 1954. (Photo by Three Lions)

A portrait of French WWI soldier Edouard Marius Ivaldi is displayed on a tablet, in this illustration picture, alongside his battlefield grave memorial, a wooden cross with a battlefield helmet in Champagne, eastern France, November 3, 2015. (Photo by Charles Platiau/Reuters)

Cosplayers dressed as characters from the Star Wars movie series visit patients during a charity event organised by non-profit group 501st Legion, at East Avenue Medical Center in Quezon city, metro Manila December 6, 2015. (Photo by Romeo Ranoco/Reuters)

Period-costumed actors participate in the 150th anniversary re-enactment of the surrender of General Robert E. Lee to General Ulysses S. Grant at the Museum of Confederacy in Appomattox, Virginia, April 9, 2015. (Photo by Jay Paul/Reuters)

People hold umbrellas as they walk past a flooded street in Taiyuan, Shanxi Province, China, July 19, 2016. (Photo by Reuters/China Daily)

People visit an art installation “Alley of Flying Umbrellas” in central St. Petersburg, Russia, May 15, 2015. Art installation inspired by “Umbrella Sky Project” of Portuguese town of Agueda and was made of 500 colored umbrellas. (Photo by Anatoly Maltsev/EPA)

A woman holds her umbrella while walking against strong winds as Typhoon Chan-hom approaches Taiwan, in Taipei, July 10, 2015. (Photo by Pichi Chuang/Reuters)