There were a very specific genre in 1970's in Italian cinema. It's called giallo in italian (literally - yellow). In italian language this word means "detective". Somebody could call it an italian film noir, but these movies had some stylistic features (e.g. special use of camera and "stupid" screenplays). I believe there were not really great movies, masterpieces in this genre, but some are really interesting and original. Maybe it isn't worth to seriously explorate giallo here. So, here are my short takes and some recommendations. Of course, everybody is welcome to contribute to the thread. 

Una lucertola con la pelle di donna/Lizard in a Woman's Skin (Lucio Fulci, 1971)
One of the best giallo movies - who would ever thought! - is created by Lucio Fulci - the author of stupid mainstream comedies and trash horror. The film is set in London: the wife of a succesfull lawyer has obtrusive dreams about licentious orgies in the apartment next door. In one of these dreams a neighbour becomes the victim of the murder - in the morning this dream becomes real. The most interesting thing in the movie is not the Inspector Corvin investigation, not screenplay. The most interesting thing in the movie is its "visual tone"- so consistent and exquisite that even the scene of a banal conversation in the drawing-room captivates with its geometrical structure; its composition is so adjusted! There are several brilliant surrealistic takes: e.g. flying shadow of the swan hunting Florinda in her dream. So, forget about stupid screenplay and enjoy visual constituent of the picture! 8/10