Where: San Jose, CA
What: Estimated 500 to 600 rooms built but only 160 remain; staircases that lead to nowhere; doors that open to nothing
Why: Sarah Winchester, wife of William Wirt Winchester, heir to Winchester rifles, believed she was haunted by the people killed by her family's rifles. To confuse spirits and lead them away, Sarah worked on extensions of her house every day. If you look closely on the right, you'll see a door on the second floor that opens up to empty space.
Source: Flickr User HarshLight