The documentary Dark Days was brought to my attention by the Opester (Underground Exploring Searching for MOLE PEOPLE). It's about homeless people who literally lived under Manhattan in the Amtrak tunnel. Beautifully shot, they focus on a few residents who all have their own stories and various backgrounds. What you hear is Salome, a doom/sludge metal band with vocalist Katherine Katz who has the one most powerful voices I've heard in my life. The band split up a while ago, but good old Katz is still kicking it with the grindcore masters of Agoraphobic Nosebleed.