A nuclear weapon is a super powerful bomb that can be launched from a long distance.

When it explodes, it destroys everything for miles around!

In 1945, it was used by the United States on Hiroshima and Nagasaki, killing over 200,000 people.

But why have such a dangerous weapon?

Between 1945 and 1964, 5 countries – the United States, Russia, China, the United Kingdom and France – made more and more powerful nuclear weapons.