The action takes place in the fictional, African-American neighborhood of Catfish Row, Charleston, South Carolina. With the exception of several minor speaking roles, all of the characters are African-American. The music combines elements of popular music of the day, with a strong influence of African-American music, of the period, with techniques typical of opera, such as recitative, through-composition and an extensive system of leitmotifs. Porgy and Bess contains some of Gershwin's most sophisticated music, including a fugue, a passacaglia, the use of atonality, polytonality and polyrhythm, and a tone row. Even the "set numbers" (of which "Summertime", "I Got Plenty o' Nuttin'" and "It Ain't Necessarily So" are well known examples) are some of the most refined and ingenious of Gershwin's compositions. For the performances, Gershwin collaborated with Eva Jessye, whom he picked as the musical Director. The work was first performed in 1935; it was a box-office failure in the middle of the Great Depression.