George Sanders, in his 1960 autobiography, wrote at length about the making of this film, which he found an exasperating and unpleasant experience. He spoke witheringly about Roberto Rossellini, whom he characterized as being more interested in scuba diving than in film-making. Although the tone of his remarks is one of amusement, it became known that Sanders (who had admired earlier Rossellini films) had been deeply affected by exposure to a style of film-making quite foreign to his previous experience, and had spent the shoot feeling frustrated and angry, often bursting into uncontrollable tears.
Alex (portrayed by George Sanders) complains several times in the film that he is bored. The suicide note Sanders left behind in 1972 said, in part, "Dear World, I am leaving because I am bored."
The structure outside the Hotel Excelsior is the Fontana del Gigante (Fountain of the Giant), a 17th-century monumental fountain. It was originally sited outside the Royal Palace of Naples. It was moved to its present site on via Partenope in 1905.
The Joyces' car is a 1950 Bentley Mk.VI drop-head coupe. In just "good" condition in 2021, a left-hand drive example of this car could be worth $150,000.