Theme(s):
baroque, optical illusions, central perspective, vanishing points
It is pretty much related to what I worked on for Sobrenatural. In general the links are not so many, because I include more wikipedia articles or textpages in my research, less video...
Baroque composer Lully
optical illusions (both links have commercials, I think?)
philosophy
Mahler, sung by Dietrich Fischer Dieskau
BONUS: more music that might not be directly related to the topic but that I like.