The Winchester Mystery House was the personal residence of Sarah Winchester, the widow of gun magnate William Wirt Winchester. The house was continuously under construction for 38 years, and is noteworthy in that it seems to lack any sort of reasonable master building plan. According to legend, Ms. Winchester thought the house was haunted by the ghosts of the people who fell victim to Winchester rifles, and believed that only constant construction would keep the spirits at bay. (Source: Winchester Mystery House)