CBS Broadcasting Inc. (commonly shortened to CBS, the abbreviation of its former legal name Columbia Broadcasting System) is an American commercial broadcast television and radio network serving as the flagship property of the CBS Entertainment Group division of Paramount Global. Headquartered at the CBS Building in New York City and being part of the "Big Three" television networks, CBS has major production facilities and operations at the CBS Broadcast Center and the headquarters of owner Paramount at One Astor Plaza (both also in that city) and Television City and the CBS Studio Center in Los Angeles. It is sometimes referred to as the Eye Network, after the company's trademark symbol of an eye (which has been in use since October 20, 1951), and also the Tiffany Network, which alludes to the perceived high quality of its programming during the tenure of William S. Paley (and can also refer to some of CBS's first demonstrations of color television, which were held in the former Tiffany and Company Building in New York City in 1950).