from wikipedia:
Progressive rock (often shortened to "progressive", "prog rock" or "prog", also called "art rock"[1]) is a form of rock music that evolved in the late-1960s and early 1970s as part of a "mostly British attempt to elevate rock music to new levels of artistic credibility."[1]
Progressive rock bands pushed "rock's technical and compositional boundaries"[1] by going beyond the standard rock or popular verse-chorus based song structures. Additionally, the arrangements often incorporate elements drawn from
classical, jazz, and avant-garde music. Instrumental songs are more common, and songs with lyrics are sometimes conceptual, abstract, or based in fantasy. Progressive rock bands sometimes used "concept albums that made unified statements, usually telling an epic story or tackling a grand overarching theme".[1]
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