Cylon is a planet covered almost entirely by one giant city. Though it used to have rolling hills, blue rivers, and high mountains, that all changed. The humans of Cylon were very intelligent when it came to technology. They created a giant computer called the Central Core. It monitored everything on the planet. When K471 took control of the planet, he used the Central Core to erradicate all life. By the time he had created the Cult Mechanicus the entire planet was one giant city/factory. Much of the planet sized city was destroyed when Cazzik Wyn, Dorset Konig, and others arrived to defeat the Cult. However, it was rebuilt and made the capital of the Cylon Imperium.