The Winchester Mystery House was built in San Jose by Sarah Winchester, the widow of Will Winchester (who worked in her father-in-law Oliver Winchester's gun business). Sarah inherited a fortune from the gun manufacturing company run by the men in her family. She was convinced after her husband's death by an occultist that the spirits of people killed by her husband's guns were trying to get to her, and that the only way to keep them at bay was to continually have work done on her house. This sounds like a completely fictional story, we know, but it's not.
It is, however, being turned into a movie starring Helen Mirren, because it's just that good:
The Smithsonian reports that Sarah paid 16 carpenters to work on her house in shifts, and they were paid three times the going rate. The work went on 24 hours a day from 1886 until Sarah died in 1922.