In ancient times, the Trolls used the Hidden Palace Zone as a mine. They dug up gems which increased their powers. It became inactive after the Trolls became nearly extinct. (SU: #88) Many years later, Dr. Eggman had come to this zone in his quest for power. He had fought Sonic the Hedgehog and Miles "Tails" Prower here, where the mad scientist was defeated and forced to retreat. (VG: StH2)