The National Broadcasting Company (NBC) is an American English-language commercial broadcast television and radio network owned by Comcast. The network is headquartered at 30 Rockefeller Plaza in New York City, with additional major offices near Los Angeles (at 10 Universal City Plaza), and Chicago (at the NBC Tower). NBC is one of the Big Three television networks, and is sometimes referred to as the "Peacock Network", in reference to its stylized peacock logo, introduced in 1956 to promote the company's innovations in early color broadcasting; it became the network's official emblem in 1979.