Pop music originated in the 1950s from rock and roll and borrows elements from other styles like urban, dance, Latin, and country music. It is defined by having short to medium length songs that highlight the chorus contrasted with the verse and use repeated choruses, melodic tunes, and catchy hooks. Typical instruments include vocals, electric guitars, drums, bass, and synthesizers. The main goal of pop music is to be pleasurable to listen to rather than having great artistic depth or meaningful themes. Famous pop singers include Britney Spears, Lady Gaga, Madonna, Beyoncé, and Michael Jackson, who is still known as the "King of Pop".