Have you ever met the savior of humanity?"In 1983, war tensions were high between NATO and the Warsaw Pact. For a few years, the USSR under Brezhnev and Andropov were terrified that a United States first strike was imminent, and had instuted the RYaN (from the Russian meaning something like "Nuclear Rocket Attack") program to find any hints of warlike intentions.
In the summer of '83, the Able Archer '83 exercises (a NATO communications exercise meant to simulate the first week of World War Three, culminating on the last day with a rehearsal of an expected nuclear exchange) were held, this coinciding with the controversial arrival of Pershing nuclear missiles. The Russians were monitoring in real time and were becoming increasingly alarmed at the exercise. The coinciding of the two events sent Soviet suspicions through the roof. And, the Soviet early-warning satellite system was fundamentally flawed.
The system registered five ICBMs from three separate launches headed towards Russia.
Stanislav Petrov, the officer in charge of the station, realized quickly that the United States would not launch a first strike with just five missiles - had they actually intended to initiate war they'd have launched everything, in an attempt to cut the head off their enemy before it could retaliate significantly. Suspecting an equipment error, he shut down the first two alarms, and explained to his superiors that he was ignoring the third, citing the fact that only five missiles had been launched. Had he instead given credence to the alarms, the Soviet Union would most likely have launched a "counter"-strike, which the USA would have correctly seen as a first strike. An actual counter-strike would have followed, and we wouldn't be reading TV Tropes right now. And, to top it all off, Petrov wasn't supposed to be the man on duty that day. He had taken the shift for another operator who was sick.
Needless to say, Petrov - the man who very literally saved humanity - was promptly relieved of duty pending an official inquiry."
http://tvtropes.org/pmwiki/pmwiki.php/Main/ANuclearError
"(For what it's worth, they decided he'd acted properly and he was reinstated.)"