Harry Potter: 20th anniversary of the Philosopher's stone film

Happy 20th anniversary to the first Harry Potter film!

That's right! - It's been 20 years since Harry Potter and the Philosopher's Stone was first released in the cinemas around the world, in 2001.

The first in the eight-part movie franchise, Philosopher's Stone introduced fans to the wizarding world, and actors, Daniel Radcliffe, Emma Watson and Rupert Grint.

Since then the films have become one of the world's most successful franchises, earning around £5.7 billion pounds.

To celebrate we're taking a look at some magical facts from the movies!

Rupert Grint found out about the Harry Potter auditions from Newsround!

That's right! Rupert Grint first heard that there would be open auditions (meaning anyone can try-out, not just professionals) for the Philosopher's Stone from watching a report on Newsround!

Check out a clip from his first official interview with Newsround back when it was presented by Matthew Price.

The audition process to be an actor in the film was pretty tough, and had three stages to it.

For the first bit auditionees had to read a page from the book, then in then next stage they had to improvise a scene where their characters arrived at Hogwarts, and in the final stage auditionees had to read some lines from the script in front of the Director, Chris Columbus.

Tom Felton, who played Draco Malfoy, said that he originally auditioned to play both Harry Potter and Ron Weasley before landing the role of Draco, and Eddie Redmayne, who plays Newt Scamander in the Fantastic Beasts movies, said he initially auditioned for Tom Riddell (young Lord Voldemort) but never heard back.

Props and costume: From wands to fake teeth

Throughout the filming for the movies Daniel Radcliffe went through around 160 pairs of glasses, and around 60-70 wands!

Harry Potter's famous scar had to be applied by the make up team more than 5,000 times, not just to Daniel, but to his stunt doubles too.

The final scene in the Philosopher's Stone at Hogwarts station was the first scene they filmed for the movie.

In it Hermione can be seen wearing some fake teeth, to make her front teeth look bigger and closer to how Hermione looks in the books, and Harry can be seen to be wearing green contact lenses.

However the director decided to lose the fake teeth and contact lenses, after Emma said she couldn't really speak very well with them in, and Daniel said the contact lenses were very uncomfortable.

The Weasley's flying car, from the Chamber of Secrets, was bought by former One Direction star Liam Payne.

He said: "I bought the Harry Potter car and I put it in my garden. You know the blue car, the flying one? I'm a bit of a geek."

Meow-gical!

Animals were a big part of the movies, from Scabbers the rat, to Crookshanks the cat!

In total, more than 250 animals were used across the Harry Potter films.

The biggest animal on the set was a hippo, and the smallest one a centipede!

According to Julie Tottaman, who trained the animals for the films, one of the hardest animals to train were the owls! She said that could take months to learn a particular trick.

In the end credits for The Goblet of Fire movie, there is a line that says: "No dragons were harmed in the making of this movie"

What's you favourite moment from the Harry Potter films?Let us know in the comments below!