The national film registry is like a magical place where important movies go to live forever. It's like a big library for movies!
Every year, a group of really smart and important people called the Library of Congress decide which movies are really special and deserve to be saved forever in the national film registry. They pick movies that are really old, or that were really important and changed the way movies are made.
Once a movie is picked for the national film registry, it gets saved on a special kind of film called "nitrate film" that will last a really long time, even longer than normal film. That way, people can always watch the movie and it will never disappear or get lost.
It's like a big treasure chest of movies that are really important, and it's fun to think about which movies might get picked next!