The National Broadcasting Company (NBC) is an American commercial broadcast television network that is the flagship property of NBCUniversal, a joint-venture between Comcast, General Electric and Vivendi. The network is headquartered in the GE Building at Rockefeller Center in New York City, with additional major offices near Los Angeles (at Universal City Plaza), Chicago (at the NBC Tower) and soon in Philadelphia at Comcast Innovation and Technology Center. The network is part of the Big Three television networks. NBC is sometimes referred to as the "Peacock Network", in reference to its stylized peacock logo, which was originally created in 1956 for its then-new color broadcasts and became the network's official emblem in 1979.