5. Hearst Castle San Luis Obispo – $190 Million
William Randolph Hearst – the publishing tycoon who inspired the movie Citizen Kane – built this sprawling estate in 1919. With 29 bedrooms, three pools, a movie theater, a nightclub and several tennis courts, the mansion could house its own little community. In 1957, shortly after the founder’s death, the Hearst Corporation donated the property to the state of California, where it is located. Its current value is $190 million.