Pink Floyd were rock's metaphysical cartographers of the collective unconscious for nearly five decades. In the early years, the band traced the peaks and valleys of kaleidoscopic '60s pop on such manic gems as “See Emily Play”, before traversing the more mannered terrain of psychedelic jazz on the classic 1973 album The Dark Side of the Moon. As the Floyd trudged into the desolate plains of The Wall and beyond, they continually expanded one of rock's darkest and most mysterious catalogues, with moody atmospherics often softening the delivery of harrowing themes and politically poignant lyrics.