On September 26, 1983, Soviet officer Stanislav Petrov saved the world.

Allegedly saved the world. It actually seems pretty unlikely that the world was saved by Petrov. For one thing, Wikipedia says:

There are varying reports whether Petrov actually reported the alert to his superiors and questions over the part his decision played in preventing nuclear war, because, according to the Permanent Mission of the Russian Federation, nuclear retaliation is based on multiple sources that confirm an actual attack.{2}.