2. Roman Holiday (1953)
You could make the mistake of thinking that William Wyler's Roman Holiday was just an excuse for its stars, Audrey Hepburn and Gregory Peck, to travel abroad, make a conventional rom-com, and sell it the masses - and you might have been right, had it not been for a few essential elements, one of which is the brilliant, giddy atmosphere that surrounds the whole picture, Hepburn's Oscar-winning performance, and - most importantly - the phenomenal, lingering ending that defied romantic comedy conventions of the time and makes the movie truly great. Having spent the day in Rome with runaway Princess Anne, newspaperman Joe has officially fallen in love - unfortunately, the princess is on a tour of Europe, and must be moving on. In the final scene, Anne address the a crow of journalists, and the pair share a final glance before she disappears. Conventions at the time would denote that - as Joe stares, waiting for her to return - Anne come running back to him... but, no, she doesn't come back, and - in a heartbreaking moment - he walks away, hands in pockets, as the orchestral score swells sadly, before giving one final glance to the place where the Princess was standing but a moment ago. The movie ends on this melancholic note, with the pair unable to continue their romance, but it's the perfect note to go out on - one that transforms Roman Holiday from a jolly romantic comedy and into a classic.