For the first time since the Sistine Chapel was built, the Pope finally allowed the Sistine Chapel Choir (active since 1471) to record professionally Miserere by the Italian composer Gregorio Allegri. I heard this one on Classic FM few weeks ago and knew straight away it will complement my scenes. The acoustic is extremely hypnotizing. This is just an extract from the whole piece.
I was thinking to add also whispers like those in TV Series Lost, so here is an example. I think those whispers represent all those souls imprisoned in the books from my scenes. Taken from http://www.freesound.org/people/qubodup/sounds/194628/
Creepy isn't it?