Nuclear weapon

A nuclear weapon is an explosive device that draws its destructive force from nuclear reactions — either fission (splitting atoms) or a combination of fission and fusion.

Power

Nuclear weapons release energy far greater than conventional explosives, capable of destroying entire cities and causing long-lasting radioactive fallout.

History

The first were developed during the Second World War, and two were used on the Japanese cities of Hiroshima and Nagasaki in 1945. Since then, treaties have sought to limit their spread.

Frequently asked questions

What is a nuclear weapon?

An explosive device powered by nuclear reactions.

When were nuclear weapons first used?

In 1945, on Hiroshima and Nagasaki.