Skaro radius, from the surface to the centre of its cold planetary core (the Ice Heart of Skaro, was about 10000 miles. Directly below the surface of Skaro was a cellular layer consisting of a network of caves inhabited by tunnel beasts. Below were the Zone of Eternal Dark, home to eerie glowing creatures the Stratum of Screaming Winds, inhabited by Suckers the Abyss of Death with its walls of living rock the depths of unknown with their masters the Krakis and finally the Morass, encasing the Ice Heart directly, domain of the sponge people | Nature