This month marks the 70th anniversary of the release of Citizen Kane. Holding the number one spot at the AFI Top 100 Movies list, it is seen by many critics to be the best film yet made. It also used many cinematography methods bringing things like deep focus into popular use.
However, the film wasn't a huge success on first run, having limited released due to theatre fears of retaliation by William Randolph Hearst's media empire. Based loosely on Hearst's life (among others), Citizen Kane was not seen kindly by the magnate. PBS' American Experience produced a documentary called The Battle over Citizen Kane that covered much of the controversy. You can read a transcript online.
While there were many sources of inspiration you can see some of them still in person. Xanadu, the fictionalized mansion in florida was based on the Hearst Castle which is now a California State Park and can be toured by visitors.