NIN: The Fragile (1999)
Five long years after The Downward Spiral (1994), its successor appeared, a double album of two distinct halves.
Disc 01 (labelled as LEFT) feels like another concept album. It's moody and seems initially impenetrable, but rewards repeated listens; like a winter retreat it reveals hidden beauty to those that choose to explore (if you can accept the notion that personal demons are a kind of beauty).
It embraces the fuzzy guitar sound that people associate with NIN, but there's much more to it - it's layered throughout with hooks and a deep resonating bass that pumps like a meticulously slow, pained heartbeat.