In September 1980 a Korean airplane moved too far into Soviet airspace. The Soviet Union shot it down killing almost 300 people. The flight included some United States Congress members. Later that same month, the Soviet early alarm system blared to life. It signaled that five missiles launched from the United States headed straight towards them.
The man in charge, Stanislav Petrov, had a decision to make. He could retaliate or call it a false signal. Ultimately, using his gut decision, he called it a false alarm. He figured that the U.S. would send more than five missiles if they wanted to attack. He made the right decision. Sun glare had tricked the sensors into the false alarm. His quick thinking averted a nuclear war that could have destroyed the planet.
Sadly, it took another 20 years before Stanislav Petrov received the honor. His actions showed the defects in the alarm system and embarrassed his superiors. Instead of praise, they stonewalled him into early retirement. Eventually, though people learned of his actions and he received the honor he deserved.