 The interior of the hall is opulently , but by the standards of the day , simply decorated and furnished . Ornament is used with such restraint that it was possible to decorate both private and state rooms in the same style , without oppressing the former . The principal entrance is through the Marble Hall , which is in fact made of pink Derbyshire alabaster ; this leads to the piano nobile , or the first floor , and state rooms . The most impressive of these rooms is the Saloon , which has walls lined with red velvet . Each of the major state rooms is symmetrical in its layout and design ; in some rooms , false doors are necessary to fully achieve this balanced effect . 
