Dixieland is a form of jazz that originated in New Orleans in the early 20th century, characterized by collective improvisation and a polyphonic ensemble sound. Ragtime is a form of jazz that developed in the late 19th century, featuring syncopated rhythms and a strong emphasis on the offbeat. BOP is a form of jazz that emerged in the 1940s, characterized by fast tempos, complex harmonic structures, and improvisation based on harmonic structure rather than melody. BEBOP is a form of jazz that developed in the mid-1940s, characterized by fast tempos, complex harmonic structures, and improvisation based on chord progressions.