Sergio Leone, 1968. Harmonica vs Frank in the post-railroad West. Ennio Morricone's most-haunting score.
From Wikipedia
Once Upon a Time in the West is a 1968 epic spaghetti Western film directed by Sergio Leone from a screenplay he co-wrote with Sergio Donati. It stars Claudia Cardinale, Henry Fonda, Jason Robards, Charles Bronson, Gabriele Ferzetti, Woody Strode, Jack Elam, Lionel Stander, Paolo Stoppa, Frank Wolff, and Keenan Wynn. The widescreen cinematography was by Tonino Delli Colli and the film score was composed and conducted by Ennio Morricone.