In 1755, a massive 9-magnitude earthquake in the Atlantic Ocean caused a 400-foot-high wave to come crashing down on Lisbon, the capital of Portugal.
It killed an estimated 60,000 people and resulting fires destroyed two-thirds of the city, according to the US National Geophysical Data Center. Waves were seen as far away as Ireland.
The event even affected European literature and philosophy. According to a 2004 article in the Yale Journal of Criticism, "the Lisbon earthquake of 1755 famously shook the metaphysical optimism of Europe's leading philosophers." The city's high death toll is believed to have underpinned Jean-Jacques Rousseau's argument for naturalist living in the countryside.
"If the residents of this large city had been more evenly dispersed and less densely housed, the losses would have been fewer or perhaps none at all," he wrote in a letter to Voltaire.
