Sherlock Jr.

A projectionist who dreams of being a detective is framed for a theft he did not commit and banished by his rival. Back in the booth he falls asleep and walks into the film on screen, becoming the world's greatest detective, Sherlock Jr. The movie inside the movie is a parade of stunts, including a famous sequence where Keaton rides on the handlebars of a motorcycle through traffic, unaware the driver has fallen off. The scene where the screen keeps cutting to new locations while Keaton stays in place was one of the earliest jokes about editing itself. Keaton wrote, directed, and performed his own stunts, and broke his neck on the water-tower gag without realizing it for years.