One more beautiful Russian Orthodox Chant:
The Polyeleos ("much oil" or, by connotation, "much mercy") is a festive portion of the All-Night Vigil service as observed on higher-ranking feast days in the Eastern Orthodox Church.
The Polyeleos consists of Psalms 134 and 135 (Septuagint numbering; King James Version: Psalms 135 and 136), which are solemnly chanted in a festive melody, with refrains Alleluia chanted between each verse. The refrain for Psalm 134 is "Alleluia.". The refrain for Psalm 135 is "Alleluia, alleluia. For His mercy endureth forever. Alleluia." This repeated chanting of the word "mercy" is another reason for the chanting of these psalms to be called Polyeleos. (from Wikipedia)
Performers: Festal Choir of St. Elizabeth Monastery, Minsk, Belarus
Conductor: Nun Irina (Denisova)
http://www.youtube.com/watch?v=KUOD22Dicjg
PS English version:
http://www.youtube.com/watch?v=coQw0qM5Cxs