The best sad music of the world is the tradicional music of Portugal
I present you Fado, feel the beauty and cry:
https://www.youtube.com/watch?v=kP6ofmjFh5Y
https://www.youtube.com/watch?v=HH6jgxfWO2Y
https://www.youtube.com/watch?v=0iL0ludUtJc
https://www.youtube.com/watch?v=AuH4__pfuzI
https://www.youtube.com/watch?v=SqWGQLKhCnc