Rock music, also known as rock'n'roll, is a genre of popular music that originated and evolved in the United States during the late 1940s and early 1950s from musical styles such as gospel, country, blues, and rhythm and blues. It is characterized by loud, amplified guitars, piano, saxophone, and drums and often lyrical themes of teen romance and rebellion against social norms. Rock music became the most commercially successful genre of popular music worldwide over the past 60 years, exerting a significant influence on youth culture and popular culture in general.