10 Last-Minute Changes That Saved Horror Movies

In Roman Polanski's psychological horror, Rosemary Woodhouse (Mia Farrow) falls pregnant after moving into a new apartment building with her partner, Guy. After a string of disturbing instances, Rosemary suspects something is wrong with her unborn child. In the end, she discovers the building's other tenants are Satan worshippers and she is about to give birth to the Antichrist.

Rosemary's Baby should be commended for its stirring writing, focus on atmosphere, eerie soundtrack, and powerful performances, especially from the lead. Also, Rosemary's Baby never feels like a schlocky B-movie, despite its outlandish plot, with the demonic imagery kept minimal and the story grounded in reality. 

However, this all could've been derailed by the original ending. 

When Rosemary looks at her son during the final scene, she's horrified by its demonic appearance. Although the infant is never seen, producer William Castle wanted a shot of the grotesque creature. Fortunately, this idea was discarded, believing it would be more haunting if the ungodly child's appearance was left to the imagination. As such, the scene focuses on Rosemary's reaction to the child, rather than the child itself - a decision that worked out perfectly, since Farrow's performance here absolutely sells this scene.