10 Biggest Unsolved Harry Potter Mysteries
A department full of mysteries.
It's been over 20 years since the release of Harry Potter and the Philosopher's Stone, and since then J.K. Rowling's Wizarding World has expanded into a further six novels, three tie-in books, a stage play (that's also another book), nine movies (with at least another four on the way), and a whole interactive website dedicated to the stories of Harry and Hogwarts.
In between finishing the book series, writing Fantastic Beasts, and continuing to work under the nom de plume Robert Galbraith, Rowling has spent a lot of time clearing up some of the series' biggest unanswered questions, revealing what happened to Hermione's parents, whether or not the trio returned to school, who killed Remus and Tonks, what Dumbledore sees in the Mirror of Erised and many, many more.
However, despite the author's best efforts, the Potter universe remains full of questions we may never know the answer to. This is, after all, a world where the Ministry of Magic had an entire department dedicated solely to mysteries that either could or would never be explained - it's no the wonder a fair few were left behind.