In 1961, the USSR dropped the most powerful nuclear bomb in history over a remote north island of the Arctic Circle. The force of the explosion was felt hundreds of kilometers away, and its power was 50 million tons in TNT equivalent. The nuclear bomb exploded about 4 kilometers above the ground, but its shockwave left the island flat and bare, resembling a skating rink. The observers saw the flash at a distance of about 965 kilometers and felt the incredible heat at a distance of about 250 kilometers.
A mushroom-like cloud has risen to the height of the edge of space. It was the RDS-220 nuclear bomb that was conventionally named the Tsar Bomb. 60 years after the historic event, none of the created nuclear bombs came close to matching its destructive power.
Recently, the state corporation "Rosatom" made a previously classified video archive of that event publicly available. It contains 40 minutes of secret videos showing the path of the bomb to the creation of a mushroom cloud. The order for the creation of the weapon came personally from Nikita Khrushchev in July 1961. His plans included getting a 100 megaton nuclear weapon, but the engineers were ultimately only able to provide a 50 megaton version.
Even with half the power requested, the bomb was incredibly powerful. It was a thousand times more powerful than the nuclear warheads that were dropped on Hiroshima and Nagasaki. In the frames of the once classified video, it is possible see how huge the Tsar Bomba was. Its weight was 27 tons, and its size was comparable to that of a double-decker bus.
A powerful aircraft bomber carried that massive weapon over the islands of Novaya Zemlya, and then a bomb was dropped with a parachute. The ensuing explosion actually knocked the plane off course, the pilot could not hold control and leveled the flight only after 900 meters.
Fortunately, not a single person was injured in the explosion. And never again has a single bomb of such power been tested on the planet. In 1963, the United States, the Union of Soviet Socialist Republics and the United Kingdom signed the Limited Test Ban Treaty that prohibited air testing of nuclear weapons.