It is stated that the interiors of the Sinking House were based on the interiors of the Hotel Danieli in Venice, Veneto, Italy. The interiors of this hotel featured in the earlier James Bond film 'Moonraker' (1979). An exterior shot of of the hotel's rooms in Venice also appeared in this earlier James Bond film.
The Purvis and Wade screenwriters refer to a documentary about the Leaning Tower of Pisa which was the initial inspiration for the sinking house in 'Casino Royale' (2006).