When a German torpedo sunk the British liner R.M.S. Lusitania on May 7, 1915, nearly 1200 passengers perished. Sure, Germany had given the world fair warning that it planned to target any of its enemies’ ships—passenger vessels included—but the tragedy still understandably shocked far-flung onlookers. And since more than 100 victims were from the U.S., Americans were especially angered.

Contrary to popular belief, however, the disaster didn’t cause the U.S. to dive headlong into World War I right then: It would be another two years before Woodrow Wilson finally asked Congress for permission to enter the fray. On this episode of Misconceptions, Mental Floss host Justin Dodd reveals how it really went down—and what other factors contributed to the decision.

That’s not the only widespread misunderstanding people have about the Great War. From who was involved (hint: not just Europe) to the roles and reputations of certain major players (e.g. Mata Hari and the Red Baron), here are all the facts behind some of the era’s most intriguing misconceptions.

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