Casablanca was based on an unproduced play titled Everybody Comes to Rick’s, written by Murray Burnett and Joan Alison. Warner Bros. purchased the rights to the play in 1942 for $20,000, a record price at the time for a work that had not been commercially successful.

Ironically, several of the actors portraying German soldiers were actually European Jews who had fled Nazi persecution.

The movie was filmed primarily over the course of just three months. A brisk schedule even by the standards of the era. Remarkably, the production often lacked a finished script, with writers sometimes delivering pages only hours before shooting.

Ingrid Bergman initially didn’t want to take the role; she was far more eager to star in For Whom the Bell Tolls, which was delayed.

Humphrey Bogart’s famous line, “Here’s looking at you, kid,” was not improvised as rumored and appeared in the script.

The oft-quoted “Play it again, Sam” is a misquotation, a classic Mandela effect. In the film, Ilsa says, “Play it, Sam. Play As Time Goes By.” Later, Rick says, “You played it for her, you can play it for me. If she can stand it, I can play it.”

The final budget was roughly $1 million, not record-breaking, but above average for a Warner Bros. production of the period.

Rick’s Café Américain was one of the few original sets constructed for the film; most of the other sets were repurposed from earlier Warner Bros. movies.

Although the story is set in Morocco, the entire film was shot on the Warner Bros. lot in Burbank, California.

The iconic airplane scene did not feature a real aircraft; it relied on a cardboard cutout enhanced with fog and wind effects.

Bergman had cut her hair for another role, which made reshoots of scenes involving “As Time Goes By” impossible, a factor that helped preserve the song despite objections from studio executives and the composer.

Rick’s bet of 10,000 francs with Captain Renault would be roughly equivalent to $3,400 in U.S. dollars today.

The original ending envisioned Rick escaping with another man’s wife, but the Hays Code prohibited that outcome, leading to the film’s noble finale where he sacrifices his love for a higher cause.

Dooley Wilson, who played Sam, was actually a drummer, not a pianist, and had to mime playing the piano while another musician performed offscreen.

Casablanca was one of four films Humphrey Bogart appeared in during 1942.