Sitting on the top of a mountain, and sporting an over-sized golden statue of Robotnik doing his pose with his arm raising forward, Dr. Robotnik's Fortress is his central base for his plots to take over Mobius and destroy Sonic in Adventures of Sonic the Hedgehog.
Damaged and destroyed on many occasions, the base has little defenses except for that of Scratch, Grounder, and Coconuts. Although it holds a massive prison block, the base is more of a home to Robotnik than an actual military base. When not having the 6-S and/or Coconuts on a mission, they are usually the ones cleaning the base. The fortress is also Sonic's usual first and last stop in preventing Robotnik's plans of taking over Mobius. It is revealed in the episode "Zoobotnik", that the golden statue of Dr. Robotnik has a flippable top, so it can become a watch tower.