A desperate German factory worker called Georg Elser decided to prevent war by assassinating Adolf Hitler in 1939. He built a time bomb and hid it in a hollowed-out pillar in the Bürgerbraukeller, a Munich beer hall where Hitler held a speech on each anniversary of the Beer Hall Putsch, when Hitler and his followers unsuccessfully attempted to overthrow the government of the Weimar Republic in 1923.
In 1939, Hitler was scheduled to speak on November 8 from 8 p.m. to 10 p.m., so Elser set the bomb’s timer to 9:20. The weather forecast, however, predicted heavy fog, which would have grounded Hitler’s plane and prevented him from returning to Berlin on the same night. The Führer decided to go home by train, but that meant he had to cut his speech short, finishing at 9:07. Had his plane been available, he would have been standing right in front of the pillar hiding the bomb at 9:20 and would have certainly died, cutting World War II short.