Questions & Answers about El final de la película me hizo pensar.
De means of, so el final de la película literally means the ending of the film.
This is a very common Spanish structure:
- el título del libro = the title of the book
- la puerta de la casa = the door of the house
- el final de la película = the ending of the film
Spanish usually uses noun + de + noun where English often uses noun + noun or possessive.