Rosemary's Baby
This slow descent into madness by Mia Farrow's character is an iconic one. As Rosemary comes closer and closer to her due date, she begins to realize that there might be something off about her baby. It doesn't help that she's got some weird neighbors next door who suggest the same. The diabolical truth of this horror movie is only revealed after the baby is born. It's both topical and surreal at the same time.