Fifty years ago the world was so worried about nuclear war that special bunkers were made to protect people if the bombs went off.
In the 1950s and 60s, children and adults thought that war was a real possibility.
Much of the world was split into two sides - on one side, Communist countries like the Soviet Union and China and on the other, capitalist countries like the USA and UK.
Both sides had enough missiles to wipe out tens of millions of people and in 1962 the world came the closest it ever has done to nuclear war.
Hayley's been to see a bunker from the time that is still there today, buried deep underground.