Citizen Kane (1941)

Continuity mistake: In the scene with the lovely dancing ladies, Cotten blows cigar smoke just before a cut to him from the opposite angle. From this angle there is no smoke. This takes place just before Wells throws his jacket to Cotten.

Charles Foster Kane: Rosebud.

Trivia: The shot of the loud, squawking bird was purposely placed by Orson Welles to make sure the audience was still awake.