There will always be new horror movies on the horizon, and they will always come in different flavors. There are those that are based on true events, and those that end with a seriously sinister twist. And of course, there are those that simply don't get the credit they deserve. Today, though, we're turning our attention elsewhere. We're talking about the kind of horror film that haunts you for weeks, months, maybe years. Throughout the course of cinematic history, there have been plenty of films like this. And, well, in case you're looking for nightmares, we've rounding up a small sampling.