Nuclear weapon

A nuclear weapon derives its destructive force from nuclear reactions of fusion or fission. As a result, even a nuclear weapon with a small yield is significantly more powerful than the largest conventional explosives, and a single weapon is capable of destroying an entire city.

In the history of warfare, two nuclear weapons have been detonated — both by the United States, during the closing days of World War II. The first was detonated on the morning of 6 August 1945, when the United States dropped a uranium gun-type device code-named "Little Boy" on the Japanese city of Hiroshima. The second was detonated three days later when the United States dropped a plutonium implosion-type device code-named "Fat Man" on the city of Nagasaki. These bombings resulted in the immediate deaths of around 120,000 people from injuries sustained from the explosion and acute radiation sickness, and even more deaths over time from long-term effects of radiation. The use of these weapons was and remains controversial.