The Cabinet of Dr Caligari is a visually stunning film. Shot in a German Expressionistic style of forced perspectives, weird angles and skewed shapes, Cabinet delivers the goods and would later inspire such filmmakers as Rowland V. Lee [Son of Frankenstein ] all the way to Tim Burton [Nightmare Before Christmas]. It is a visual delight from start to finish.
However, this is not the only reason to enjoy Cabinet. It may very well be the first zombie film ever created. The central characters include Dr. Caligari and his "somnambulist" Cesare, who has been under Caligari's control for 23 years. A somnambulist is a sleepwalker and Caligari can get him to do whatever he likes. The relationship is not unlike that which we see in White Zombie (1932) where Bela Lugosi mind controls the slaves on his Haitian plantation. While Cesare is not the gut-munching Romero type zombie, one could argue this character is ground zero in the zombie mythos.
The final reason to enjoy Cabinet is the performances of Werner Krauss as Caligari and Conrad Veidt as Cesare. Krauss absolutely looks the part of the "mad scientist" and has a creepy aura about him. It's hard to believe he was 35 when he made this film. Kudos to the makeup department! Veidt is perfect as Cesare. His slow movements and piercing eyes embody the character with a sense of dread that is fun to watch. For a modern visual comparison, think of Johnny Depp in Tim Burton's Edward Scissorhands.
For some horror fans, silent films seem rather boring. It's true their pacing is slower. But give this one a chance. Be patient and enjoy the wonderful rewards this film has to offer. You can download this one free from Archive.org but the print is pretty dark. My suggestion is to view one of the restored versions that have been made since 2000.
Download a copy of the film from Archive.org
For more info check out the film's entry in IMDB.