The Winchester Mystery House is a mansion in San Jose, California, which was once the personal residence of Sarah Winchester, the widow of gun magnate William Wirt Winchester. Located at 525 South Winchester Blvd. in San Jose, the Queen Anne Style Victorian mansion is renowned for its size, its architectural curiosities, and its lack of any master building plan. It is a designated California historical landmark and is listed on the National Register of Historic Places. It is privately owned and serves as a tourist attraction.