Three secondary schoolboys smoking an illicit cigarette in Hyde Park, London. (Photo by Evening Standard/Getty Images). May 1972

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

Australian actress Joy Smithers poses beside a poster featuring Australian cricketer Brett Lee during the official launch of the AceStar underwear range at Pink Salt on August 19, 2008 in Sydney, Australia. (Photo by Mike Flokis/Getty Images)

Television actress Catherine Fuller visits Trafalgar Square in London and feeds the famous pigeons. (Photo by Harry Kerr/BIPs/Getty Images). 26th June 1956

A steam traction engine with a broken rear axle in Pall Mall, London. (Photo by Topical Press Agency/Getty Images). November 1923

Private Harold L. Langhofer edges into the ball-turret, March 9, 1943. Curled in this position, he can turn the turret so that it fires in any direction. The turret can also be swung around so that the hatch opens into the plane, and the gunner can crawl into it while the Flying Fortress is in motion. (Photo by AP Photo)

“A fter the former Soviet Union conducted its first nuclear test in August 1949, the US reevaluated its postwar defense policies. With the US monopoly on atomic weapons broken, military and political leaders chose to diversify the American stockpile by developing thermonuclear and tactical nuclear weapons. One of the more interesting concepts to come out of this period was atomic artillery, which was successfully tested at the Nevada Proving Grounds (now the Nevada Test Site) in May 1953”. – Alan Carr. Photo: Atomic Annie at work during the Upshot-Knothole test series, 1953. (Photo by Los Alamos National Laboratory/US Army)

A tourist poses for a picture with the Sphinx at the Pyramids of Giza in Cairo, Egypt, on October 19, 2011. (Reuters/Jamal Saidi)