1. Dumbledore’s telescope is engraved with the signs of the zodiac. It was one of the most expensive props used during filming.
2. Daniel Radcliffe went through 60 to 70 wands throughout all eight movies.
3. Apple juice was often used as a replacement for Butterbeer.
4. About 250 body casts were made of actors for deaths, petrifications, and stunning spells.
5. Professor Umbridge’s plates in Harry Potter and the Order of the Phoenix were created by filming kittens on a green screen.
6. The Howler was designed with origami in mind.
7. Each Death Eater mask was created with its own identifiable design.
8. The Chamber of Secrets door is fully functioning.
9. Another version of Tom Riddle’s diary that could weep ink from its pages was created.
10. The texture and color of Peter Pettigrew’s wig was designed to match the animatronic Scabbers the rat’s fur.
11. It’s rumored that the house points counter shown in the Great Hall caused a national shortage of Indian glass beads.
12. Many of Diagon Alley’s set pieces were repurposed as Hogsmeade for Harry Potter and the Prisoner of Azkaban.
13. The flame that came from the Hungarian Horntail’s mouth was so hot that it turned the animatronic dragon’s snout red.
14. The neck from the Basilisk was reused to create the neck of the Hungarian Horntail.
15. The welcome feast in Harry Potter and the Goblet of Firewas created with a mixture of edible pieces and desserts made from painted resin.
16. The cat who played Mrs. Norris once jumped up and stole a sandwich from David Bradley, who played Filch.
17. There was no stand-in for Buckbeak, but a deerhound was used as a stand-in for Harry’s Patronus.
18. Each of the chandeliers in Gringotts bank features more than 25,000 crystals.
19. Over a dozen fireplaces, each more than 30 feet high, were created for the Ministry of Magic set.
20. Inside the hundreds of potion jars lining the walls of the Potions classroom were baked animal bones from a local butcher shop and dried leaves and herbs.
21. More than 300 fiber-optic lights were installed in the Hogwarts model so as to simulate lanterns, torches, and the illusion of students passing through the hallways.
22. Three mechanical versions of The Monster Book of Monsters were created: one you held in your hands, one that snapped open and fired shredded paper, and one with a blue pole that was later removed with visual effects.
23. Each memory vial in Dumbledore’s Memory Cabinet got its own handwritten label.
24. The Sword of Gryffindor was bought at an auction and then partly redesigned.
25. Professor Umbridge’s outfits used fabrics with a fibrous nap to “create a glow” around her.
26. The skyline etched on the outside of the golden egg from Goblet of Fire is meant to depict an unspecified historical city.
27. The staircase leading up from the Gryffindor Common Room spirals up to a hallway that, in one direction, leads to the boys dormitory and, in the other direction, leads to a doorway that drops off into nowhere.
28. Hedwig was played by several male snowy owls including Elmo, WTON, Gizmo, and Sprout.
29. More than 60 unique Goblin faces were made for the final film.
30. The Knight Bus was created from three vintage London double-deckers.
31. For eight nights over eight weeks, London streets were shut down so the film crew could maneuver the Knight Bus around.
32. Several Invisibility Cloaks were made. The one seen in Harry Potter and the Sorcerer’s Stone is made up of a special velvet fabric and has Celtic symbols and ancient runes printed on it.
33. Many of Dumbledore’s books are actually just old phone books with leather and dust covering them.
34. It took more than 300 liters of silicone to make the candy in Weasley’s Wizard Wheezes.
35. The Magic Is Might monument at the Ministry of Magic was chiseled out of foam and then painted to look like stone.
36. British steam train No. 5972, aka “Olton Hall,” was used as the Hogwarts Express throughout the film series. Crew members scoured the country for it and found it at a preservation center in Lancashire.
37. Snape’s robes are one of the only costumes that never changed throughout the series.
38. Approximately 950 visual and special effects were used during the veil room scene (a record for the film series).
39. The Aragog animatronic had an 18-foot leg span and was created with yak hair, sisal (a plant from the agave family), and hemp from brooms.
40. Seventeen thousand hand-decorated and hand-labeled wand boxes filled the Ollivanders set during filming.
41. Professor Slughorn’s Potions classroom used to be Snape’s office, and before that it was the room with the trapdoor that Fluffy was guarding.
To find out more about the Warner Bros. Studio Tour in London, head on over to its official website.