It's a truth universally acknowledged that Christmas movies are one of the best parts of Christmas. We've grown up with them, and we all have one or two favorite we know practically by heart.

And like every film, there are always some facts you didn't know.

Home Alone (1990)

1. Macaulay Culkin's stunt double was not a child. It was a very short 30-year-old man.
2. The line, "Keep the change, ya filthy animal!" is not from a real gangster movie, but one created especially for the scene.

It's a Wonderful Life (1946)

1. Even though it's set around Christmas, the film was shot during a heat wave. The cast had to take two days off because the excessive heat made their costumes unwearable.
2. The "Bedford Falls" set was one of the longest sets ever been made for an American film.

Elf (2003)

1. Will Ferrell got several headaches throughout filming, because he had to actually eat all the food Buddy ate.
2. Filming caused several minor traffic accidents in the Lincoln Tunnel,  where real-life drivers were shocked to see Will Ferrel walking by in an elf costume.

A Christmas Story (1983)

1. Ralphie's father was never given a name. He is only referred to and credited as "The Old Man".
2. The house Ralphie's family live in in the film, is now an A Christmas Story museum in Cleveland Ohio.

Miracle on 34th Street (1947)

1. Natalie Wood still believed in  Santa when Miracle on 34th Street was filmed.
2. Kris Kringle's beard was not real. Edmund Gwenn could not grow a beard "Santa-esque" enough.

And now you have another excuse to go back and watch them all.