Ask HN: Facts you learned at school which aren't true any more?

Starting from a video of Scott Manley https://www.youtube.com/watch?v=1wIZ2sp39Cc I become very curious and excited to find out more subjects/topics like these. What facts you learned at school are not true anymore? Edit: I also found this link https://www.quora.com/Education/What-are-some-facts-still-being-taught-in-school-that-have-been-proven-to-be-false which was posted also on HN two years ago.