Casablanca (1942)

The Film: Craggy-faced drunk runs a gambling den in Morocco, bumps into ex and her new beau, tries to win her back, but decides defeating the Germans is more important and helps her escape. Regrets it every day.

Why it works as a stand-alone feature: The definitive romance, Casablanca has all the drama, thrills and itear-jerking moments to keep Kleenex in business for centuries to come.

Where the franchise could have gone: All the bars in all the world, and this is the only one they used? There’s a trilogy in there somewhere.

Paris: A prequel to Casablanca, documenting the beginning of the affair with Ilsa in the French capital, and also showing some of Rick’s prior escapades in the Spanish Civil War.

Barcelona: In 1975, after the death of dictator Francisco Franco and the end of the Nationalist government, Rick travels to Barcelona to spend his twilight years among friends from the Civil War.

A chance meeting with an aged Ilsa, now a widow, rekindles the romance of a lifetime, with the pair finally given a chance to spend the rest of their lives together – but Rick is unwell, and they don’t have much time left.

Next: Gladiator