The extremely emotional opening theme of the 1977 film combines with its unusual credits sequence (a series of impressionistic oil paintings) to make for quite a memorable experience. From the plaintive cry of "Who will rescue me?", the score gradually builds up to a climax (around two minutes in) that wouldn't sound out of place in an Ennio Morricone score. It's uncharacteristic for Disney, and heartbreakingly beautiful.
"Someone's Waiting for You", heard when Penny stands outside downtrodden but with a glimmer of hope that she'll be rescued and adopted. Simple lyrics, but a beautiful message that's also relatable for anyone who was raised in a broken home. The scene goes into Tear Dryer when Penny smiles during the line "Have faith, little one."