Blow-Up, Michelangelo Antonioni's 1966 "mod masterpiece" about a fashion photographer who believes he accidentally caught a murder on film, defied the movie industry's Production Code of the time, a code abandoned in favor of the MPAA film rating system in 1968 due largely to the success of this film.
Herbie Hancock scored the movie which was ranked No. 144 in the Sight and Sound magazine greatest films poll. It is definitely at the top of my list. Check it out.