A polar bear fast asleep at London Zoo. (Photo by Fox Photos/Getty Images). 1961

A baby bush-baby in a set of scales at London Zoo shortly after birth. (Photo by Fox Photos/Getty Images). 10th August 1938

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

A chimpanzee bottle-feeds a lamb at Southam Zoo Farm in Warwickshire. The owners of the zoo, Mr and Mrs Clews, bring up many of the animals as their pets; the animals, are, as a result, of a friendly disposition. (Photo by Fox Photos/Getty Images). 23rd August 1968

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

A worker pauses for a sandwich, resting on a girder during the construction of a skycraper. (Photo by Hulton Archive/Getty Images). Circa 1930

Three workers demonstrating the different types of gas masks used in mine rescue work. (Photo by Fox Photos/Getty Images). December 1925

A dejected German Grenadier carrying a machine gun on his shoulder in front of a building on fire during the German retreat in Russia. (Photo by Keystone/Getty Images). 1944