1 Adam: So, Count Dracula, what sort of Dungeons & Dragons adventures do you run?
2 Dracula: Enchoy classics. Willage of Hommlet. Against the Chiants. Vite Plume Mountain. Tomb off Horrors.
3 Jamie: Ever run Ravenloft? Or maybe Curse of Strahd?
4 Dracula: Oh! They so unrealistic.

Ravenloft has been mentioned in these annotations a few times. It was the first gothic horror adventure for D&D, leaning heavily on vampire tropes as popularised by Bram Stoker's Dracula. It was also revolutionary for other reasons, containing a fortune telling prelude that randomised some of the important elements of the adventure, such as the locations of significant items and the motives of the lead villain, the Count Strahd von Zarovich. This meant that people could play the adventure multiple times and be surprised each time. It also contained the first use of isometric 3D maps in an adventure module.

The D&D 5th Edition rules conversion of this adventure, Curse of Strahd expands the original adventure by adding a wilderness sandbox around the Castle Ravenloft, containing multiple new NPCs and side quests. It's a huge, sprawling adventure that lends itself to a long campaign rather than a few sharp sessions of play. In my opinion, it's one of, if not the best of the 5th Edition adventures that Wizards of the Coast has released, but that's not really saying much as I think almost all of the others have been very disappointing.