It's been ten years since the Harry Potter and the Half-Blood Prince" pushed this beloved fantasy saga in a darker direction, complete with a tragic death and new insight into the origins of the wizarding world's greatest villain. Celebrate this milestone by learning more about the making of the sixth Potter movie.

1. "The Half-Blood Prince" is the third-longest movie in the series, falling behind only "Harry Potter and the Goblet of Fire."

2. The actor who plays the 11-year-old version of Tom Riddle, Ralph Fiennes.

3. Though roughly 7,000 girls auditioned for the role of Lavender Brown, Emma Watson.

4. This is the first film in the series not to feature any Defense Against the Dark Arts classroom scenes, despite the fact that Professor Snape is revealed to have taken over the class early in the film.

5. Director David Yates said the film's color and lighting were heavily inspired by the work of Dutch painter Rembrandt. Fittingly, this is the only film in the series to be nominated for the Best Cinematography Oscar.

6. While Yates has directed every "Harry Potter" and "Fantastic Beasts" movie since "Harry Potter and the Sorcerer's Stone" years before.

7.Kevin McKidd was approached to play werewolf villain Fenrir Greyback, but had to decline due to his other commitments. McKidd has since said he doesn't regret turning down the part, as it would have terrified his children.

8.Harry Potter and the Deathly Hallows: Part 1."

9. The set used for Professor Slughorn's office is a modified version of the same one used for the Trophy Room in "The Goblet of Fire" and the Room of Requirement in "The Order of the Phoenix."

10. Actor Die Hard" and pointing out how his character got to be on the opposite end of a battle involving one character falling to their death.

11. Narcissa Malfoy actress Helen McCrory was originally cast as Bellatrix Lestrange in "The Order of the Phoenix," but left the project after becoming pregnant.