Some tunes from the world of classical music that are incredibly beautiful:

Bruckner - Locus Iste
Faure - Cantique de Jean Racine
Handel - La Paix, from Music for the Royal Fireworks
Mendelssohn - For He Shall Give His Angels Charge Over Thee, from Elijah
Mozart - Andante, from Eine Kleine Nachtmusik
Schubert - Morgengruss, from Die Schone Mullerin
Vivaldi - Spring, from The Four Seasons