4. Jethro Tull
This legendary British group features flute-wielding frontman Ian Anderson and has evolved their sound throughout the years, starting as a blues-rock band and eventually incorporating classical, jazz, folk and hard rock elements. In the early 1970s they recorded back-to-back concept albums, each with only a single song (1972’s Thick as a Brick and 1973’s A Passion Play).
The English rock band achieved success with their combination of progressive, art and symphonic styles. They are known for their use of mystical/cosmic lyrics, live stage sets and lengthy compositions which often contain complex instrumental and vocal arrangements. They are one of the most popular, influential and critically-acclaimed acts in the history of the progressive genre.