Tsar Bomba (Царь-бомба, literally "Emperor Bomb") is the Western name for the RDS-220 hyrogen bomb (codenamed "Иван" (Ivan) by its developers) — the largest, most powerful nuclear weapon ever detonated. Developed by the Soviet Union, the bomb was originally designed to have a yield of about 100 megatons of TNT; however that was reduced by half in order to limit the amount of nuclear fallout that would result. Two bombs were built, a mock bomb and the real bomb, with the real bomb being tested on October 30, 1961, in the Novaya Zemlya archipelago. Despite testing, the weapon never entered service; it was simply a demonstration of the capabilities of the Soviet Union's military technology at that time. The mock bomb was stored in the Russian Nuclear Weapons Museum in Sarov.