30th October 1961: The Tsar Bomba detonated by the USSR

The Soviet Union tested its first nuclear bomb in 1949, four years after the USA had become the world’s first nuclear superpower. Determined to catch up with their rival in the West, successive Soviet governments invested heavily in the nuclear program and by 1961 they had successfully detonated more than 80 devices. Nichita Khrushchev, who had been the Soviet leader since 1953, was particularly keen to position the USSR as the dominant nuclear power. With his encouragement a team of physicists designed what was to become the most powerful man-made weapon ever created. Known by various codenames, it soon became known in the West as the Tsar Bomba. A specially adapted Tu-95V bomber carried the enormous bomb to the remote Novaya Zemlya archipelago in the Barents Sea, north of the Arctic Circle. Measuring 8 metres (26 ft) long by 2.1 metres (6 ft 11 in) in diameter, the weapon weighed 27 metric tons and contained three stages that had a yield of more than 50 megatons. This was more than 1,500 times the power of the Hiroshima and Nagasaki bombs combined, yet the bomb was capable of twice this if some of its uranium had not been replaced with lead. The bomb was dropped from an altitude of 34,000ft. A parachute then slowed its descent to give the aircraft time to get away before it detonated at 13,000ft. Even so, the crew had only a 50% chance of survival. The explosion caused a fireball that was visible 630 miles away while the shock wave orbited the world three times, breaking windows as far away as Norway and Finland. No weapon of this power has been detonated since.