The Legends of Classic Rock and Folk Rock Playing their Hits! 24-7 Legends is based on the legends of Classic Rock and Folk which is a radio format developed from the album-oriented rock (AOR) format in the early 1980s. In the United States, the classic rock format features music ranging generally from the mid-1960s to the late 1980s, primarily focusing on commercially successful rock popularized in the 1970s.