Some other people are mentioning this, but I thought it was worth repeating.
On this day, in 1983, Stanislav Yevgrafovich Petrov decided not to report a probable missile launch from the US, on his own authority.
It was later found to be sensor error, but doctrine for both superpowers at that time was a massive retaliatory strike. If Russia had struck back, the US would have counter-retaliated, almost certainly killing hundreds of millions of people.
Stanislav Petrov, by virtue of his position, his sound judgement, and historical situation, saved your life, and that of almost everyone you know.
He does not consider himself a hero, and perhaps he is not. But he is Responsible, in a way that few people are, for our current situation. It was his judgement that prevented nuclear war. And that’s worth commemorating.