The Great Dictator (1940)
And the end of the film brings a downright somber ending to the rest of the laugh-fest. However I think this is 100% on purpose, and brings the entire film to a sharp point. Without it, I doubt it would have carried the same punch, and would have been dismissed as just another comedic journey. The monologue here is one of the best written and moving bits I’ve heard in a long time.
I highly recommend this film, if nothing else just to see Chaplin in a rare speaking role, and his ability to execute such a serious-yet-dead-funny picture.