The Hydrogen Bomb. pic: 1952. A picture of the thermo-nuclear device tested by the U.S. at the Elugelab test island in the Marshall Islands . The picture is taken from 50 miles distant and at 12,000 feet shows the early stage of the cloud formation which [Getty Images]

The Hydrogen Bomb, pic: 1952, A picture of the thermo-nuclear device tested by the U,S, at the Elugelab test island in the Marshall Islands , The picture is taken from 50 miles distant and at 12,000 feet shows the early stage of the cloud formation which eventually extended 25 miles up and spread for 100 miles (Photo by Popperfoto via Getty Images/Getty Images) — see more

The Hydrogen Bomb, pic: 1952, A picture of the thermo-nuclear device tested by the U,S, at the Elugelab test island in the Marshall Islands , The picture is taken from 50 miles distant and at 12,000 feet shows the early stage of the cloud formation which eventually extended 25 miles up and spread for 100 miles (Photo by Popperfoto via Getty Images/Getty Images)

Russian politician and Premier Nikita Krushchev (1894 - 1971) (left) moves to hug Cuban Premier Fidel Castro as the latter arrives for dinner at the Soviet legation, New York, New York, September 23, 1960. The men were in New York for the 15th General Assembly of the United Nations. (Photo by PhotoQuest/Getty Images) — see more

Russian politician and Premier Nikita Krushchev (1894 - 1971) (left) moves to hug Cuban Premier Fidel Castro as the latter arrives for dinner at the Soviet legation, New York, New York, September 23, 1960. The men were in New York for the 15th General Assembly of the United Nations. (Photo by PhotoQuest/Getty Images)

BERLIN, GERMANY: Since August 1961, horizon for East Berliners was limited to contemplating this 4 meters high wall on which hundreds of escape candidates injured themselves, while others died trying to flee the tyranny of German communism - The Berlin Wall, raised by Erich Honecker, runs 164 kms long, surrounding the entire city of West Berlin, and manned by 14.000 border guards(Photo by Pool MUR DE BERLIN/Gamma-Rapho via Getty Images) — see more

BERLIN, GERMANY: Since August 1961, horizon for East Berliners was limited to contemplating this 4 meters high wall on which hundreds of escape candidates injured themselves, while others died trying to flee the tyranny of German communism - The Berlin Wall, raised by Erich Honecker, runs 164 kms long, surrounding the entire city of West Berlin, and manned by 14.000 border guards(Photo by Pool MUR DE BERLIN/Gamma-Rapho via Getty Images)

Students at a Brooklyn middle school have a 'duck and cover' practice drill in preparation for a nuclear attack; silver print, 1962. From the New York World-Telegram archive. (Photo by GraphicaArtis/Getty Images) — see more

Students at a Brooklyn middle school have a 'duck and cover' practice drill in preparation for a nuclear attack; silver print, 1962. From the New York World-Telegram archive. (Photo by GraphicaArtis/Getty Images)

Washington DC, USA, 18th June 1973, Russian Premier Leonid Brezhnev (left) and American President Richard Nixon are pictured prior to their White House talks (Photo by Popperfoto via Getty Images/Getty Images) — see more

Washington DC, USA, 18th June 1973, Russian Premier Leonid Brezhnev (left) and American President Richard Nixon are pictured prior to their White House talks (Photo by Popperfoto via Getty Images/Getty Images)