Director Dario Argento said he experienced stendhal syndrome as a child. While touring Athens with his parents young Dario was climbing the steps of the Parthenon when he was over come by a trance that caused him to become lost from his parents for hours. The experience was so strong that Argento never forgot it and immediately thought of it when he came across Magherini's book, which would become the basis of the film.
Graffiti artists were brought in to cover the underground lair of Alfredo with graffiti. In one night the group created over a hundred square feet of graffiti-covered walls on the location.
Stendhal Syndrome is a real syndrome, first diagnosed in Florence, Italy in 1982. Named after the French writer Stendhal AKA Marie-Henri Beyle who reportedly experienced like symptoms in 1817.
Though featuring prominently during the film's opening sequence set at the Uffizi in Florecne, Peter Bruegel's 'Landscape with the Fall of Icarus' is actually housed at the Royal Museum of Fine Arts of Belgium in Brussels.