Tsar bomb 1400 times more powerful than Hiroshima, Nagasaki 
The Tsar Bomba which was detonated by the Soviet Union on October 30, 1961 in northern Russia is believed to be 1,400 times more powerful than Hiroshima and Nagasaki bombings combined. Also called 'Big Ivan', it is known as the largest nuclear weapon ever detonated. It is also believed that it had ten times the explosives used in WWII bombings.