the moon," "Valley of the Shadow"- In Eldorado the “mountains of the moon” and “the Valley of Shadows”
are biblical images. In the Bible they represent places where life ended and death began. They both represent the Knight “walking”
or riding to his death. It means that he dies trying to find Eldorado.
this is imagery for the “pilgrim” who is really a ghost telling the knight his way to the afterlife.