This is the 30-room and 16,000 square foot Whittier Mansion built in 1896 by William Franklin Whittier, the CEO of what later became the Pacific Gas and Electric Company.
It survived the 1906 earthquake and stayed in the family until Whittier's death in 1917 when he was 85. His children sold the mansion in 1938 to the Deutsche Reich and was the German Consulate for a while. In the post-war years it was used as a Philosophical institute until 1956 when it became home to the California Historical Society. Now it is a private home.
However rumors persist that the servant's quarters and the wine cellar are haunted by a ghost. Some say it was Whittier himself, but others think it is his son Billy, a ladies man and bon vivant, helping himself to a bit more wine.