Tsar Bomba was the largest, most powerful nuclear weapon ever detonated. Developed by the Soviet Union, the bomb had a yield of about 50 megatons of TNT. The bomb was tested on October 30, 1961 in Novaya Zemlya, an island in the Arctic Sea. The subsequent mushroom cloud was about 60 km high (nearly seven times higher than Mount Everest) and 30–40 km wide. Atmospheric focusing caused blast damage up to 1,000 km away.