The Tsar Bomba weighted 27 tons and had a yield of 50 megatons; 1350 times more powerful than the bomb dropped on Hiroshima. It was test fired in 1961, or more accurately, it was released by a modified Tu-95 Bear. Upon release, the bomb deployed an 800-kilogram / 1,600-square-metre parachute designed to slow down the fall of the bomb and give the plane and pilots an estimated 50% chance of escaping the blast and survive… The bomb detonated at an estimated altitude of 4,000m. By the time the shockwave caught up with the Tu-95V, the bomber was 115km away. The force of the wave was such that the plane dropped 1km in altitude before the pilot managed to regain control of his aircraft. The blast registered up to 5 on the Richter’s scale. The flash was seen 1000km away and an abandoned village 55km away from the blast site was flattened. The shockwave circled the earth 3 times, cracking windows up to 900km away. As for the mushroom cloud, it reached an altitude of 64 kilometres, that’s 7 times the height of Mount Everest. Some of the energy released by the bomb actually escaped the earth’s atmosphere!
Plans to detonate similar bombs to the Tsar Bomba (or bigger ones) were subsequently abandoned.