Blues music is a genre that originated in the African American communities of the Deep South of the United States in the late 19th century. It combines elements of African musical traditions, spirituals, and folk songs, often expressing themes of sorrow, hardship, and resilience. The typical structure of blues music includes a 12-bar format and the use of specific chord progressions, which create a distinctive sound. Instruments commonly used in blues include the guitar, harmonica, and piano. Notable artists like B.B. King and Muddy Waters have significantly influenced the genre, helping to shape its evolution and popularity. Blues music has also laid the groundwork for many other genres, including rock and roll and jazz.