Rivers of music

Down the Volga, Mother Volga (Вниз по матушке по Волге) is a Russian folk song, here performed by Feodor Chaliapin (and a choir). The scene is from a 1960 U.S.S.R film Girls’ Summer (Девичья весна).
This is a vocal arrangement; note that no instruments are employed.
In Russia, folk songs are merged with religious chants and choral songs. It remains difficult to tell a folk song apart from a choral song. As the Orthodox church imposed, for several centuries, a ban on any instrumental music, all talented musicians wrote vocal arrangements exclusively for the church.
In this way, the entire musical soul of the Russian people was poured into the Orthodox church. There were no instruments; the musical arrangements were carried by voices alone. This made church service a personal and emotional experience that can only be compared to that of African-Americans singing gospels at mass.
In Russia, to quote Chekhov, the village church was the only place where a peasant could experience something beautiful. And so much more than that; peasants were not performing, they were creating. Their singing gave life to a stream of music and they made it flow on all the way to the enchanted sea.

Barge-haulers' shanty

The Song of the Volga Boatmen, by Paul Robeson (1938). This song is a genuine shanty of the Volga barge-haulers. An earlier 1922 recording, performed by Feodor Chaliapin in original Russian, is enchanting.
The original lyrics, in Russian and English both, can be found here. Please note that Robeson only in parts stayed true to the original.
Paul Robeson, in an interview, explained that "[t]he African people have an almost instinctive flair for music. This faculty was born in sorrow. I think that slavery, its anguish and separation - and all the longings it brought - gave it birth. The nearest to it is to be found in Russia, and you know about their serf sorrows. The Russian has the same rhythmic quality - but not the melodic beauty of the African. It is an emotional product, developed, I think, through suffering."