The advent of cable and satellite television has greatly expanded sports offerings on American TV. ESPN, the first all-sports cable network in the U.S., went on the air in 1979. It has been followed by several sister networks and competitors. Some sports television networks are national, such as CBS Sports Network, Fox Sports 1 and NBC Sports Network, whereas others are regional, such as NBC Sports Regional Networks, Fox Sports Networks and Spectrum Sports. General entertainment channels like TBS, TNT, and USA Network also air sports events.