Just after midnight on September 26, 1983, Soviet satellite operators at the Serpukhov-15 bunker just south of Moscow got a warning that a US Minuteman nuclear missile had been launched. Later, four more missiles were detected.
Tensions between the US and Soviet Union were strained earlier in the month, when the Soviets shot down Korean Air Lines Flight 007 near Sakhalin Island, killing all 269 people on board — including US Congressman Larry McDonald.
The commanding officer at the bunker, Stanislav Petrov, was to inform his superiors of the launches, so an appropriate response could be made. Soviet policy back then called for an all-out retaliatory strike.
Knowing this, Petrov decided not to inform his superiors. "All I had to do was to reach for the phone; to raise the direct line to our top commanders — but I couldn't move. I felt like I was sitting on a hot frying pan," he recalled of the incident.
He reasoned that if the US were to strike the Soviet Union with nuclear weapons, they would send hundreds of missiles, not just five.
But Petrov had no way of knowing if he was right until enough time had passed, by which time nuclear bombs could have hit their targets, arguably making his decision the biggest gamble in human history.
After 23 minutes, Petrov's theory that it was a false alarm was confirmed. It was later discovered that a Soviet sattelite had mistaken sunlight reflecting off the top of clouds as missiles.