Club/Dance music comes in many different forms, from disco to hip-hop. Though there have been various dance crazes throughout the history of popular music, club/dance music became its own genre in the mid-'70s, as soul mutated into disco and whole clubs were devoted to dancing. In the late '70s, dance clubs played disco, but by the end of the decade, disco was mutating into a number of different genres. All of the genres were collected under the catch-all term "dance," though there were distinct differences between dance-pop, hip-hop, house, and techno, among other subgenres. What tied them all together was their emphasis on rhythm – in each dance subgenre, the beat remains all-important.