High Quality Content by WIKIPEDIA articles! Grant Park Music Festival (formerly Grant Park Concerts) is an annual ten-week classical music concert series held in Chicago, Illinois, USA. It features the Grant Park Symphony Orchestra and Grant Park Chorus along with featured guest performers and conductors. The Festival has earned non-profit organization status. It claims to be the nation`s only free, outdoor classical music series. The Grant Park Music Festival has been a Chicago tradition since 1931 when Chicago Mayor Anton Cermak suggested free concerts to lift spirits of Chicagoans during the Great Depression. The tradition of symphonic Grant Park Music Festival concerts began in 1935.