Not everyone can say they single-handedly say they saved the world, but Soviet Officer Stanislav Petrov can.

In Sept, 1983, he was left in charge of a command centre near Moscow, when one of his computers told him that the U.S. had sent 5 intercontinental ballistic missiles his way. He was supposed to inform his superiors, which would have caused a counter attack resulting in mutually-assured destruction.

Instead, he waited. Relying on his judgement, he did some exploring of his systems and found that a solar alignment had messed with his radar satellite and given him a false alarm. Had he not done his due diligence, we’d all be living in a nuclear wasteland.