A jazz musician is an artist who plays jazz music, a genre that originated in the early 20th century in the United States. Jazz is characterized by its swing and blue notes, call and response vocals, polyrhythms, and improvisation. Musicians often play instruments such as the saxophone, trumpet, piano, or double bass, and they may also sing. Jazz musicians often perform in bands or ensembles, which can vary in size from small combos to large orchestras. They frequently participate in live performances at venues like clubs, festivals, and concert halls. Notable jazz musicians include Louis Armstrong, Duke Ellington, and Miles Davis, who have significantly influenced the genre.