Rock in Opposition (RIO) was a musical movement that emerged in the 1970s, characterized by its avant-garde approach to rock music, blending elements of progressive rock, free jazz, and experimental music. The movement was initiated in 1978 by a coalition of progressive rock bands who sought to promote artistic integrity and creative freedom, rejecting the commercialism of the music industry. Notable bands associated with RIO include Henry Cow, Univers Zero, and Art Zoyd, whose music often features complex structures, unconventional instrumentation, and a focus on improvisation. RIO events and festivals were held to showcase these innovative artists, fostering a sense of community among musicians dedicated to pushing the boundaries of rock music.