On this day in 1969, the music world was introduced to a groundbreaking sound with the release of Chicago Transit Authority, the debut album from the band that would soon become simply Chicago .

Blending jazz, rock, and blues, the double album showcased the band’s signature horn-driven arrangements, setting them apart from their contemporaries. Produced by James William Guercio, the record featured standout tracks like Does Anybody Really Know What Time It Is?, Beginnings, and Questions 67 and 68.

Despite initial skepticism from Columbia Records, the band insisted on releasing a double album, a bold move for a debut. Their gamble paid off—Chicago Transit Authority became a sleeper hit, eventually reaching No. 17 on the Billboard 200 and remaining on the charts for an impressive 171 weeks, breaking previous records.

The album’s success earned Chicago a Grammy nomination for Best New Artist, and in 2014, it was inducted into the Grammy Hall of Fame. More recently, in 2025, the Library of Congress selected the album for preservation in the National Recording Registry, recognizing its cultural and historical significance.

Chicago’s debut was more than just an album—it was the beginning of a musical legacy that would span decades, influencing countless artists and redefining the fusion of rock and jazz.