When I was in elementary school, teachers told me that Columbus discovered America. When I was in high school - that there are nine planets in the Solar system, including Pluto. After algebra lessons in high school, I knew for sure that Fermat's Last Theorem had no proof...
Do you know what those all have in common? Yes, that's right - some time passed, literally several years, and everything that the teacher said turned out to be untrue. More precisely, not even a lie - just science convincingly refuted everything that was considered an indisputable truth earlier. And I'm not alone here - in this thread in the AskReddit community, many netizens share similar stories from their own school years.