1961 –The most powerful nuclear weapon the world has seen was detonated by the Soviet Union. Tsar Bomba was 1,400 times Hiroshima and Nagasaki combined and ten times the entire combined fire power expended in WWII.The resulting fireball had a radius of nearly 10,000 vertical feet and its 210,000 foot tall mushroom cloud reached into the stratosphere. The light generated by the reaction could be seen from over a 1,000 km and the force of its explosion registered a 5.0 on the Richter scale. The shock wave generated air pressures topping 300 PSI, circled the Earth thrice, and cracked windows 900 km away in Norway and Finland. Buildings in the abandoned town of Severny 55 km away were leveled—all of them—and upon later inspection, ground zero was reportedly the texture of a skating rink. As one observer recalled, “The clouds beneath the aircraft and in the distance were lit up by the powerful flash. The sea of light spread under the hatch and even clouds began to glow and became transparent. At that moment, our aircraft emerged from between two cloud layers and down below in the gap a huge bright orange ball was emerging. The ball was powerful and arrogant like Jupiter. Slowly and silently it crept upwards…. Having broken through the thick layer of clouds it kept growing. It seemed to suck the whole earth into it. The spectacle was fantastic, unreal, supernatural.” This utter destruction is only half of what the Tsar Bomba was capable of. It was designed and built to deliver a staggering 100 megaton payload. The Tsar was supposed to utilize fast-fissioning uranium tampers on the second and third stages of the bomb, which would have allowed for a bigger reaction and subsequent energy release. However, just before the test was to take place, Soviet leadership ordered the tampers swapped out with lead replacements in order to prevent nuclear fallout from reaching populated areas of the USSR. These lead tampers cut the bomb’s yield by 50 percent but they also eliminated 97 percent of the resulting fallout. As such the Tsar Bomba, the largest, most destructively powerful device ever built by man also holds the notable distinction of being the relatively “cleanest” nuclear weapon ever tested. Luckily, that record was only important for two years until the signing of the Partial Test Ban Treaty which brought an end to above-ground nuclear weapons tests.