Learn Something Fun: The number 1 haunted house in America is the Winchester Mystery House.

In 1881, Sarah Winchester, the widow of famous gun maker Oliver Winchester, became convinced that she needed protection from the evil spirits of all the people killed by Winchester rifles.

A psychic advised her to continually add rooms to her San Jose, California, mansion to confuse any ghosts that may try to find her. (It’s not clear why ghosts, which can supposedly move through walls, would be confused by the rooms, but it apparently made sense to Winchester.)

She did so for nearly forty years, adding more than 100 rooms and staircases, until her death in 1922.

After Sarah’s death, her own ghost was said to haunt the halls of her mazelike mansion. Today the building remains a popular tourist attraction, a bizarre monument to superstition and paranoia.