Dancers at the Windmill Theatre in London, England practice a routine wearing gas masks and hard-hats with their costumes, 1940. (Photo by Hulton Archive/Getty Images)

A British woman plays a piano designed especially for people who are confined to bed. Date: 1935. (Photo by Mary Evans Picture Library/Caters News)

A woman dancing on the Sphinx. A pyramid can be seen in the background. (Photo by Fox Photos/Getty Images). 1928

A Thorneycroft motor van as used during World War I. (Photo by Topical Press Agency/Getty Images). August 1914

A female Chinese People's Liberation Army soldier looks at members of an honor guard preparing for a welcome ceremony for visiting German President Joachim Gauck, outside the Great Hall of the People in Beijing, Monday, March 21, 2016. (Photo by Andy Wong/AP Photo)

A soldier of the French Foreign Legion holding his regiment's banner at Bar Hacheim in Libya, circa 1940. (Photo by Three Lions). P.S. All pictures are presented in high resolution.

A new type of tandem at Alexandra Palace, London. (Photo by Fox Photos/Getty Images). June 1936

Men at work at the Cardiff Institute, making huge baskets, unique in size and construction, for loading oil cake in South Africa. (Photo by Maeers/Getty Images). 1938