Hymn of the Cherubim
Pyotr Ilyich Tchaikovsky (1840–1893) is best known for works such as the 1812 Overture and ballets like The Nutcracker and Swan Lake. Less well known is his choral version of the Liturgy of John Chrysostom, which he wrote in 1878. It contains a piece titled "The Hymn of the Cherubim."
In my opinion, it is one of the most beautiful pieces of choral music ever written.