ROCK......... 

By far the most popular music after 1955 was rock music, which was at first called Rock 'n' Roll. This music had its beginnings in the Blues and Jazz-influenced vocal music popular among African-American audiences after World War II. The country Blues traditions of the South were further influential sources of rock music. In the 1970s long rock songs, usually at fast tempos and with skipping rhythms became known as disco music. The popularity of Rock was the main reason that phonograph records became a billion dollar business in 1967. Among the performers who helped to boost the popular record sales in the 1970s were Rod Stewart, Elton John, Al Green and Steive Wonder.  
 

Another type of Rock music is Punk Rock. The main feature of this was its lyrics - despairing, violent condemnations of the dishonesty of the British ruling class. Punk also made a sleazy fashion statement - torn clothes and garishly colored hair, with razor blades and safety pins for decoration.
Heavy metal is another very loud style of rock. It features guitars, with their sounds distorted by fuzz-tone devices and techniques that make their amplifiers screech.