I always thought “Lara’s Theme” from “Dr. Zhivago” was one of the prettiest melodies ever.
There really are so many good ones tho. “Oklahom” from “Oklahoma”. The theme from “Chariots of Fire”, also “Exodus”
My high school class of 65 had “Climb Every Mountain” from “The Sound of Music” as our class song, but my favorite from that musical was “Edelweiss”.
It's so hard to choose because there were so many.
Rhapsody on a Theme from Paganini from Somewhere in Time
Dances with Wolves theme song (I love the late John Barry's music)
First song in Sense and Sensibilities