I was going through traditions when I came up with Polyphony. People using their voices in which multi-line singing is accompanied by choral drone parts, and which has many regional and formal variations.
Greece and Albania are two countries that sing polyphonic, but it goes all over Balkan. This kind of singing where mainly legends and stories, love stories and lamentations, happiness and anger.

Polyphonic songs from Epirus
Albanie, Pays Labe, plaintes et chants d’amour (Albania, Labe Country, Complaints and Love Songs)