The Election Year: 1902, in Saint-Pierre, on the French-owned Caribbean island of Martinique
The Huge Blunder: Governor Louis Mouttet's poor decision to treat Mt. PelÃ©e, Saint-Pierre's burgeoning volcano of a neighbor, like a particularly nasty attack ad. Worried that a panic would hurt his Progressive Party's showing at the polls, Mouttet chose to downplay the possible natural disaster. He first ordered the local paper to ignore the story. Then, three days before the May 11th election, Mouttet made a grand show of traveling to Saint-Pierre himself—despite a bevy of natural warning signs, including enough ash fall to cover the nearby village.
To Mouttet's credit, there was no such thing as a volcanologist at the time. All he had to go on was the mountain's past activity, which bordered on mildly annoying, at worst. But PelÃ©e's reputation (and Mouttet's) changed forever on May 8, when a searing hot cloud of gas rushed down the mountain, engulfing Saint-Pierre.
In an instant, nearly 30,000 people died — including Mouttet.
In fact, per most accounts, only one man in the entire city proper lived through the eruption—Louis-Auguste Cyparis, a prisoner who survived incineration thanks to his windowless, underground cell. He was pardoned for his troubles and went on to a brilliant career with the Barnum & Bailey Circus.
---This summer, mental_floss is re-running parts of "The 20 Greatest Mistaikes in History," Maggie Koerth-Baker's cover story from March-April 2007. To order the back issue, click here. To see other installments in this series, click here.