The Great Train Robbery introduced parallel editing to show two events happening at once

Edwin S. Porter’s 'The Great Train Robbery' was a masterclass in narrative efficiency, condensing a complex heist into 12 minutes across 20 separate shots. Its most significant contribution was the use of parallel editing, where the film cuts between the bandits' escape and the telegraph operator's daughter alerting a posse. This technique convinced audiences that these two events were happening at the exact same time.