Tsar Bomba

Tsar Bomba was the largest, most powerful nuclear weapon ever detonated. The 50 megaton bomb was detonated on October 30, 1961 at an altitude of 4,000 meters over a Siberian island in the Arctic Sea. The resulting fireball was seen 1,000 kilometers away, and broke windows in Finland. The seismic shock traveled around the world three times before dropping below measurable levels. The Soviets has designed a 100 megaton bomb, but had to scale back for testing, because they had no place to test it. You can see a longer video on the bomb here, or a shorter one here. (via Videosift)