Background: Construction of this house dates back to 1592, but it didnt acquire its trademark slant until 1718, when the structure was rebuilt using unseasoned green oak. Why Its Unique: Sure its slanted, but what really makes the house stand out is that its basement had a secret passage to Windsor Castle, one of the official residences of the UKs royal family. According to the houses website, the passage was allegedly used for trysts between King Charles and a mistress, as well as for running supplies to the castles kitchen. The passageway has since been sealed off. Through the centuries, the crooked house has been the home to various businesses, including a brewery and jewelry shop. It is now a restaurant.