A member of the German wireless police picks up signals on the radio equipment he carries on his back, while his colleague takes notes. (Photo by General Photographic Agency/Getty Images). Circa 1925

A Mark IV tank, part of the parade at the Lord Mayor's Show in London. (Photo by Topical Press Agency/Getty Images). November 1917

A workman takes a siesta on a girder during the building of Radio City, the city of New York spread out below. (Photo by General Photographic Agency/Getty Images). Circa 1933

Ernie Lotinga, looking terrified as a gun is pointed in his face, in a scene from the play “My Wife's Family”, at the Garrick Theatre, London. (Photo by Sasha/Getty Images). 24th February 1941

A group of women wearing dresses representing flags of the Allied powers (left to right: the USA, France, Britain and the Soviet Union) outside the Eglise de la Madeleine on VE Day in Paris, 8th May 1945. (Photo by Keystone/Hulton Archive/Getty Images)

West German police arrest a young man, one of the angry crowd throwing stones at a bus full of Soviet guards making their way to the Soviet War Memorial, 20th August 1962. The crowd were incensed by the death of 18-year-old Peter Fechter, who was shot while trying to cross the Berlin Wall a few days earlier. (Photo by Central Press/Hulton Archive/Getty Images)

Judy, a black collie whose owner was killed by a train when trying to retrieve her after she slipped her lead. (Photo by Evening Standard/Getty Images). 17th December 1976

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