Jazz is a music genre that originated in the African-American communities of New Orleans, United States, in the late 19th and early 20th centuries, and developed from roots in blues and ragtime. Jazz is seen by many as "America's classical music". Since the 1920s Jazz Age, jazz has become recognized as a major form of musical expression. It then emerged in the form of independent traditional and popular musical styles, all linked by the common bonds of African-American and European-American musical parentage with a performance orientation. Jazz is characterized by swing and blue notes, call and response vocals, polyrhythms and improvisation. Jazz has roots in West African cultural and musical expression, and in African-American music traditions including blues and ragtime, as well as European military band music. Intellectuals around the world have hailed jazz as "one of America's original art forms".