Tsar Bomba: the Most Powerful Bomb Ever Detonated
On 30 October 1961 the Soviet Union detonated the most powerful explosive device ever built. Officially item AN602, the bomb went down in history as the Tsar Bomba — the King of Bombs. Its yield of about 50 megatons equalled roughly 3,300 Hiroshima explosions, delivered in a single flash over the Arctic archipelago of Novaya Zemlya.
A 100-megaton design fired at half power
The weapon was a three-stage thermonuclear design about 8 metres long and weighing 27 tonnes. As designed it would have reached about 100 megatons, but for the test the uranium fusion tampers were replaced with lead. This halved the yield and, crucially, kept the shot comparatively «clean»: about 97% of the energy came from fusion, producing far less fallout than a full-power version would have. Even so, the full 100-Mt configuration was never tested — its fallout and the impossibility of the drop aircraft escaping made it impractical. You can compare both on the map: the actual 50-Mt test at Novaya Zemlya and a hypothetical 100-Mt burst over New York.
The test
A specially modified Tu-95 bomber released the bomb from 10,500 metres on a huge parachute, giving the crew time to fly about 45 km before detonation at 4,000 metres — and even then the aircraft was dropped a kilometre by the shock wave. The fireball was roughly 8 km across; the mushroom cloud rose about 64 km, seven times the height of Everest. The flash was visible 1,000 km away, wooden houses were destroyed and windows broken in settlements hundreds of kilometres from ground zero, and the atmospheric pressure wave circled the Earth three times.
Why nothing bigger was ever built
The Tsar Bomba was as much a political statement as a weapon — it was too heavy for any missile and its destructive radius grows only with the cube root of yield, so one giant bomb is far less efficient than several smaller warheads spread out. Both superpowers drew the same conclusion: accuracy beats size. Within a decade the arms race had shifted to multiple smaller warheads per missile, as described in how nuclear weapons work.
Legacy
The test came at the height of Cold War tension, days before the 50-year record it set was written into the 1963 Limited Test Ban Treaty's backstory: worldwide fallout concerns from shots like this one pushed the powers to ban atmospheric testing. The Tsar Bomba remains a singular event — see it in context on the history of nuclear testing page, or load it over any city in the simulator.
