WBBM-TV (channel 2) is a television station in Chicago, Illinois, United States, serving as the market's CBS network outlet. Owned and operated by the network's CBS News and Stations division, the station maintains studios on West Washington Street in the Loop, and it transmits from atop the Willis Tower. History. Early history (1940–1953) WBBM-TV traces its history to 1940 when Balaban and Katz, a subsidiary of Paramount Pictures, signed on experimental station W9XBK, the first all-electronic television facility in Chicago.
https://en.wikipedia.org/wiki/WBBM-TV