Every eerie scene counts. A classic Robert Towne screenplay. You can feel the rot and decadence. In the way John Huston talks. In the seen it-all face of a private dick who hasn't seen anything yet.
Evil is personal and political and pervasive.
I've been to Xanadu. Hearst's San Simeon castle which was the model for Kane's mountain top retreat. The scale is smaller but the decadence just as woozy. Crammed with Medieval tapestries and booty. A gothic chapel doubles as a dining hall.