Petrov Day is a tradition celebrating Soviet military officer Stanislav Petrov, who played a key role in preventing a nuclear attack during a false alarm incident on September 26, 1983.

Further reading

Yudkowsky, Eliezer (2007) 9/26 is Petrov Day, LessWrong, September 26.

 human extinction | nuclear warfare | Stanislav Petrov | Vasili Arkhipov