The “original” Jurassic Park. This stop-motion dinosaur film (which predates even King Kong) is something of a forgotten milestone in cinema.
The Lost World (1925)
https://www.youtube.com/watch?v=BGQfgjCXDoU - from the Classic Movie Central YouTube channel (1 hour 42 mins long - 720p)
Synopsis:
The first film adaptation of Sir Arthur Conan Doyle’s classic novel about a land where prehistoric creatures still roam.
Directed by Harry O. Hoyt.
Cast: Bessie Love, Lewis Stone & Wallace Beery.
Trivia:
This was the first feature-length film to feature stop motion animation as the primary special effect. The effects were done by Willis O’Brien who would in 1933 work on the original King Kong.