She Wore a Yellow Ribbon (1949)

In the second of director John Ford's "cavalry trilogy":

• the sunset scene of soon-to-be retired Capt. Nathan Brittles (John Wayne) sitting at the gravestone of his wife Mary Cutting Brittles and speaking to her while he watered the flowers
• the cinematographically-beautiful dark line of clouds and lightning in a thunderstorm as the cavalry patrol passed through director Ford's favorite scenic locale - Monument Valley
• the scene of his last day when Brittles' C troops gave him a silver pocketwatch with the inscription "Lest we forget" that he tearfully read with his glasses