Chicago is second only to the Beach Boys as the most successful American rock band of all time. The group formed officially on February 15, 1967, in the city from which it eventually would take its name. Chicago's music was a mixture of styles, from hard rock to light pop, incorporating elements of jazz and classical, but after Cetera's "If You Leave Me Now" became a gold-selling #1 hit in 1976, the group became more identified with romantic ballads than anything else.