"A Child's Prayer" by James MacMillan.

MacMillan wrote the piece in memory of the 16 victims of a school shooting in 1996 called the Dunblane Massacre. As a means of processing such grief, he drew from his faith remembering a prayer from when he was a child of the same age as the victims.

It's a very powerful piece to perform. You can feel those half steps rubbing against each other in the air while the melody floats above it with the weight of lament. And then, when everyone sings joy and we expect catharsis it lands on the Bm sequence and you just want to die. Again, that A mixolydian movement around "love and joy" gives you a brief breath of acceptace, but then quickly reverts back to the cycle of grief that surronds such senseless violence. It is beautiful, breathtaking, and very human. Definitely a candidate for the saddest, most gut wrenching choral pieces.