Complex sentence: National Geographic Channel is a subscription television network, launched by the Fox International Channels, which launched in 2001 and for the first 12 years, has only been available to the subscribers of NOVA Greece satellite bouquet.
Split into simpler sentences: National Geographic Channel is a subscription television network, launched in Greece in 2001 by the Fox International Channels. For the first 12 years the channel was available only to the subscribers of NOVA Greece satellite bouquet.