We all think about the Cuban Missile Crisis as the time we came the closest to nuclear war during the cold war.
On May 23rd, 1967, the US radar system designed to detect incoming Soviet missiles went dark. They thought they were being jammed - and prepared to launch a nuclear strike.
They were told to stand down just in time.
The cause? A massive solar flare. Thankfully it happened just after our first space weather monitoring systems were put in place.
And while this was kept quiet - no doubt to avert panic - it resulted in an increased investment in monitoring the sun, which has helped protect communications satellites and the like from more recent solar flares.
But we came a lot closer than I like to think about.