The Winchester Mystery House is a well-known California mansion that was under construction continuously for 38 years and is reputed to be haunted. It once was the personal residence of Sarah Winchester, the widow of gun magnate William Wirt Winchester, but is now a tourist attraction. Under Sarah Winchester's guidance, construction on the house continued 24 hours a day, seven days a week, 365 days a year, until her death 38 years later on September 5, 1922. The cost for such constant building has been estimated at about US $5.5 million.
The mansion is renowned for its size and lack of a master building plan. According to popular belief, Sarah Winchester thought the house was haunted by the ghosts of individuals killed by Winchester rifles, and that only continuous construction would appease them. It is located at 525 South Winchester Blvd. in San Jose, California.