In my biased opinion best folk music in the world is Georgian.
If you want to know what do the mountains sound like just listen to Georgian choirs.
My opinion is biased because I'm Caucasian and also live in Georgia.
I remember when I was a kid in my grandfather's house in Ingushetia. Old people would come for prayer once every 2-3 month, they would sit at the table and sing the Muslim prayer in a similar polyphonic style like Georgian choirs. Georgian songs are also mostly religious ones.

Fun fact: Georgian folk song Chakrulo was one of 29 musical compositions included on the Voyager Golden Records that were sent into space on Voyager 2 on 20 August 1977.

https://youtu.be/A2aRMt0s_kA