Buster Keaton's Amazing Stunts had a huge influence on everyone in visual comedy, from the Three Stooges to Jackie Chan. A visual gag is comic bit or effect that depends on sight rather than words and he was the undisputed master.
Clips used: Three Ages, Cops, Day Dreams, Sherlock Jr., One Week, Hard Luck, Neighbors, The General, Steamboat Bill, Jr., Seven Chances, Our Hospitality, The Bell Boy