Chicago is an American rock band formed in 1967 in Chicago, Illinois, calling themselves the Chicago Transit Authority in 1968 before shortening the name in 1969. The self-described “rock and roll band with horns” blended elements of classical music, jazz, R&B, and pop music. They began writing songs with politically charged lyrics, and later moved to a softer sound, generating several hit ballads. The group had a steady stream of hits throughout the 1970s and 1980s.
While gaining some success as a cover band in Chicago called The Big Thing, the group began working on original songs. In June 1968, the Big Thing moved to Los Angeles, California, signed with Columbia Records and changed its name to Chicago Transit Authority. It was while performing on a regular basis at the Whisky a Go Go nightclub in West Hollywood that the band got exposure to more famous musical artists of the time. Subsequently, they were the opening act for Janis Joplin and Jimi Hendrix.
Their first record (April 1969), Chicago Transit Authority, was a double album, which is rare for a band's first release. The album made it to No. 17 on the Billboard 200 album chart and sold over one million copies by 1970. The album included a number of pop-rock songs – "Does Anybody Really Know What Time It Is?", "Beginnings", "Questions 67 and 68", and "I'm a Man" – which were later released as singles. For this inaugural recording effort the group was nominated for a Grammy Award for 1969 Best New Artist of the Year.
According to Peter Cetera, the band was booked to perform at Woodstock in 1969, but promoter Bill Graham, with whom they had a contract, exercised his right to reschedule them to play at the Fillmore West on a date of his choosing, and he scheduled them for the Woodstock dates. Santana, which Graham also managed, took Chicago's place at Woodstock, and that performance is considered to be Santana's breakthrough performance.
After the release of their first album, the band's name was shortened to Chicago to avoid legal action being threatened by the actual mass-transit company of the same name.