Space Colony ARK was the most advanced research center of its kind, built more than fifty years before the events of the Sonic Adventure 2.
The ARK was used by the government for scientific testing and experimentation, and housed some of the world's finest minds in the most advanced research center of its kind. One such scientist was Professor Gerald Robotnik, grandfather of Doctor Eggman, many of whose inventions remained aboard the ARK until being reactivated many years after his death. It is particularly notable as the "birthplace" of Shadow the Hedgehog and the Biolizard.