unified statements, usually telling an epic story or tackling a grand overarching theme. King Crimson's 1969 début album, In the Court of the Crimson King, which mixed powerful guitar riffs and mellotron, with jazz and symphonic music, is often taken as the key recording in progressive rock, helping the widespread adoption of the genre in the early 1970s among existing blues-rock and psychedelic bands, as well as newly formed acts. The term was applied to the music of bands such as Yes, Genesis, Pink Floyd, Jethro Tull, Soft Machine, Electric Light Orchestra, Procol Harum, Hawkwind, and Emerson, Lake & Palmer. It reached its peak of popularity in the mid-1970s, but had mixed critical acclaim and the punk movement can be seen as a reaction against its musicality and perceived pomposity. Many bands broke up, but some, including Genesis, ELP, Yes, and Pink Floyd, regularly scored Top Ten albums with successful accompanying worldwide tours. Glam rock Glam or glitter rock developed in the UK in the post-hippie early 1970s. It was characterised by "outrageous" clothes, makeup, hairstyles, and platform-soled boots. The flamboyant lyrics, costumes, and visual styles of glam performers were a campy, playing with categories of sexuality in a theatrical blend of nostalgic references to science fiction and old movies, all over a guitar-driven hard rock sound. Pioneers of the genre included David Bowie, Roxy Music, Mott the Hoople, Marc Bolan and T. Rex. These, and many other acts straddled the divide between pop and rock music, managing to maintain a level of respectability with rock audiences, while enjoying success in the UK singles chart, including Queen and Elton John. Other performers aimed much more directly for the popular music market, where they were the dominant groups of their era, including Slade, Wizzard, Mud and Sweet. The glitter image was pushed to its limits by Gary Glitter and The Glitter Band. Largely confined to the British music scene where it originated, glam rock peaked during the mid-1970s, before it declined in the face of punk rock and new wave trends. It has had a direct influence on acts that rose to prominence later. Hard rock/Heavy metal With roots in blues-rock, psychedelic rock and garage rock the bands that created heavy metal developed a thick, powerful sound, characterised by overt rhythmic basslines, highly amplified distortion, extended guitar solos, emphatic beats, and overall loudness. Heavy metal lyrics and performance styles often incorporated