<human>:  What is the history of jazz music?
<bot>: Jazz music is an improvisational form of music that originated in the late 19th and early 20th centuries in the United States. African Americans are credited with creating this genre of music through a combination of African and European influences.Early jazz was rooted in ragtime and the blues. It was heavily influenced by West African folk music and saw popularity in the form of New Orleans street bands and the works of Jelly Roll Morton and Louis Armstrong.Jazz underwent a number of transformations over the decades, from swing, bebop and hard bop in the 1940s and 1950s to jazz-rock fusion in the 1970s to more experimental forms of jazz in the 1980s and 1990s. In the 21st century, modern jazz is still a popular form of music that continues to evolve.