BBC News:

In the early hours of the 26th of September in 1983, the Soviet Union’s early-warning systems detected an incoming missile strike from the United States. The protocol for the Soviet military would have been to retaliate with a nuclear attack of its own.

But duty officer Stanislav Petrov – whose job it was to register apparent enemy missile launches – decided not to report them to his superiors, and instead dismissed them as a false alarm.

His decision may have saved the world.

Chilling story and terrifying to think what might have happened.