The Koln Concert by Keith Jarrett was recorded on January 24, 1975 and released as a double-album with one piece for every side, that is, Parts I-IV. It was during the period when Jarrett would come out on stage, sit down behind the keys and improvise an entire show. Sure, he came with pre-conceived melodic and harmonic ideas but then, doesn't all music build on what's come before? There's the old jazz proverb: you can't play a note that hasn't been played.
It's snowing outside and this is a perfect record to fall asleep to.