History · August 1945
Hiroshima and Nagasaki, 1945
The bombs, the missions, the death toll, the survivors and the aftermath of the only two nuclear weapons ever used in war.
Guide · The physics
How nuclear weapons work, explained simply
How a nuclear bomb works in plain language: fission and fusion, gun-type and implosion designs, why yield is measured in kilotons, and what the blast, heat and radiation actually do.
History · 30 October 1961
Tsar Bomba: the biggest explosion humans ever made
The story of Tsar Bomba, the 50-megaton Soviet hydrogen bomb tested over Novaya Zemlya in 1961: how it was built, what the explosion did, why it was cut down from 100 megatons, and why nobody ever built one again.
Explainer · The nine nuclear states
Who has nuclear weapons, and how many
The nine countries with nuclear weapons and their estimated warhead counts, which missiles carry them, how the numbers have changed since the Cold War, and what the treaties say.
Guide · Survival
What to do in a nuclear attack: the first hour, the first day, the first week
Practical, official-guidance-based steps for surviving a nuclear explosion: the flash, the blast wave, getting inside, the fallout window, the 7:10 rule, and what to keep at home.