I heard this soul-stirring piece composed by Johann Sebastian Bach while watching an episode of the now-defunct Emily Owens MD. I loved it so much that I noted down its title and searched it on youtube. (Thank God for youtube and the internet!) Check it out here, performed by Denise Djokic.
video uploaded in youtube by cbcradio3
There's just something about a cello's sound that is so powerful and moving. It perfectly matches the melody of this hauntingly beautiful piece.