Strength of the most powerful nuclear weapons since 1945

To this day, the atomic bombings of Hiroshima and Nagasaki remain the only instances in history where nuclear weapons were used in warfare. The weapons used in these attacks had blast yields equal to 16 kilotons and 21 kilotons of TNT respectively, and resulted in the immediate deaths of over 100,000 people, over 200,000 deaths by the year's end, and they each destroyed a significant portion of these cities. However, the strength of the bombs used in the Second World War pale in comparison to those developed by the United States and Soviet Union in the decades that followed.

American tests

By 1954, the United States had developed nuclear weapons with yields equal to 15 Megatons of TNT, almost 1,000 times stronger than the bomb used in Hiroshima less than ten years before. In total, public information states that the U.S. developed and tested four weapons with yields greater than 10 MT. The United States used its facilities in Nevada and the Marshall Islands for much of its nuclear testing, with Bikini Atoll in particular used as the site of its three largest tests. These activities resulted in long-term low-level radiation causing some regions to become inhospitable for native populations, who suffered much higher levels of cancer and other medical side effects in the decades that followed - much of the Pacific population was forcefully relocated by the U.S., and the Bikini Atoll remains largely uninhabited to this day. In total, the United States conducted over 1,000 nuclear weapons tests between 1945 and 1992, whereby the end of the Cold War brought the Nuclear Arms Race to a halt, and the process of nuclear disarmament began.

Soviet tests

The Soviet Union developed and tested at least four known atomic weapons that were larger than any tested by the U.S.. The largest nuclear weapon ever was the Tsar Bomba, with a blast yield of 50 megatons (over 3,000 times larger than Hiroshima) - the Tsar Bomba had been capable of creating a blast equal to 100 MT, but this was reduced in order to limit the nuclear fallout. The Tsar Bomba, along with the other three largest nuclear weapons ever tested, were all detonated at the Soviet testing sites at the Novaya Zemlya archipelago in the Arctic Ocean - this was the primary testing sites for the Soviet nuclear weapons program during the cold war, along with the site at Semey, Kazakhstan, before the Partial Test Ban Treaty of 1963 banned all nuclear weapons testing in the atmosphere, ocean, or space, therefore all testing moved underground thereafter.