Chicago formed in Chicago, Illinois, in 1967 by musicians Walter Parazaider, Terry Kath, Danny Seraphine, Lee Loughnane, James Pankow, Robert Lamm, and later Peter Cetera. Initially called The Big Thing and then Chicago Transit Authority, the group relocated to Los Angeles in 1968 and signed with Columbia Records under producer James William Guercio. They blended rock with horns, drawing from jazz, soul, and politically charged themes in their early work. The band's debut album, Chicago Transit Authority (1969), featured extended compositions and tracks like 'Make Me Smile' and '25 or 6 to 4,' which reached the Top 10. Over their career, they released 37 albums, sold more than 100 million records worldwide, and shifted toward ballad-oriented rock in later decades. Early albums incorporated jazz-rock and soul influences, while hits from the 1970s and 1980s sustained their chart presence. Chicago is known for live performances emphasizing their horn section alongside rock instrumentation, delivering high-energy sets that highlight both original material and covers from their formative years.