The Kid

From Wikipedia:

The Kid is a 1921 Charlie Chaplin film. It featured Jackie Coogan as his adopted son and sidekick. It was a huge success, and was the second-highest grossing film in 1921, behind The Four Horsemen of the Apocalypse.

The Kid is about a Tramp (Chaplin) that finds an abandoned baby in an alley and takes care of him. As the baby gets older, they are perfect together and they form little schemes to scam people in order to survive.

The Kid is notable as being the first feature length comedy film to effectively combine comedy and drama, as one of the opening titles says: "A picture with a smile, and perhaps a tear..." The most famous and enduring sequence in the film is the Tramp's desperate rooftop pursuit of the welfare agents who have taken the child, and their emotional reunion. Audiences of the time were deeply affected by the film and the relationship of the Kid with the much-loved Tramp character, from whom they had not previously seen such emotional depth.