1.There was a significant decrease in the number of children who went to A&E after Order of the Phoenix and Half-Blood Prince were released. – KellyLizzyLucky
4.There isn't a translation of "I am Lord Voldemort" in Swedish. The anagram had to be translated into Latin instead. – Erika Drewke, Facebook
5.In the French version of the books, a wand is called a "baguette magique". – jenniewood
6.And the French translation of Hufflepuff is "Poufsouffle". – Jessica Shelleman, Facebook
7.J.K. Rowling revealed in 2015 that everyone had been pronouncing Voldemort's name wrong. You're not ~actually~ supposed to pronounce the T at the end. – hermanfreakinpotter
8.The fourth book is so long because, when J.K. Rowling was halfway through writing it, she realised she had created a plot hole that she had to go back and explain. – samanthak4700e333c
9.Natalie McDonald – a minor character who was sorted into Gryffindor in Goblet of Fire – was named after a real person. – Stephanie Joy Bouley, Facebook
10.The Harry Potter books are a large part of the reason the New York Times Bestsellers List has a children's category. – Sam Kramer, Facebook
11.The type in Order of the Phoenix is half a point smaller than in the rest of the books, meaning it's even longer than it looks. – Alyssa Feller
12.There's a moment in Half-Blood Prince where Slughorn accidentally refers to Ron as "Rupert" – and it was written afterRupert Grint was cast as Ron. – lexiep47feca8cf
14.J.K. Rowling never originally intended to kill Lupin and Tonks, but decided they had to go after she saved Arthur Weasley in Order of the Phoenix. – idyemyhairalot
15.Professor Trelawney mentions that her great-grandmother's name was Cassandra. Cassandra was a woman in Greek mythology who was gifted the power of prophecy. – Sajambbu Manu, Facebook
16.And Salazar Slytherin was named after a Portuguese dictator, António de Oliveira Salazar. – thaliav4a358e737
17.A 16-year-old boy was arrested in France in 2007 for posting his translation of Deathly Hallows online before the official version was published. – Ellie Bate
18.The saying "I open at the close" is true for the books – the story of the final book, Deathly Hallows, begins in 1997, when the first book was released. – rachelh4b61c04a5