Robotropolis is a heavily industrialised city populated entirely by the robotic creations of Dr. Robotnik. In the Archie Sonic the Hedgehog comics and the SatAM animated series, Robotropolis served as the seat of power in Robotnik's globe-spanning dominion. It was once known as "Mobotropolis" and was the capital of the Kingdom of Acorn, the most prosperous kingdom on Mobius. However, when Robotnik betrayed King Maximillian and took his throne, he quickly converted the city into a polluted, mechanical wasteland. Robot factories, weapons laboratories and chemical plants are constantly churning out deadly toxins into the environment. Everything that once resembled the old Mobotropolis has been torn down and remade, or simply left abandoned and derelict. Robotnik's fortress stands where the Royal Palace once stood, where he and his lackey/nephew Snively reside as the city's only organic occupants.
For ten years, Robotnik ruled Mobius from the smog-infested sanctity of Robotropolis, hatching numerous schemes to spread his pollution across the planet and destroy his enemies - the Freedom Fighters. When the doctor met his demise during the comic's Endgame saga, Robotropolis was left abandoned and wide open for the Freedom Fighters to move in and restore their once beautiful city. The reconstruction effort had barely progressed at all when Dr. Eggman arrived from another dimension to take his Prime counterpart's place. His new SWATbot army drove the Mobians back to their forest hideout of Knothole, and he re-established control of the city for a time. However, sometime after the discovery of the human city of Station Square, Eggman had made a powerful new enemy. The government of Station Square authorized a nuclear assault against Robotropolis, but Eggman had established a shield dome around the city to protect it. Knowing that the nuclear fallout would destroy the surrounding environment, Sonic and the Freedom Fighters infiltrated Robotropolis in order to disable the shield temporarily so that the nuclear warheads could get inside, then reactivate it remotely so that the missiles would detonate inside the shield, destroying Robotropolis without harming anything beyond the city. The plan was successful and Robotropolis was levelled, but Dr. Eggman (who was a robot at the time) survived by transferring his consciousness into a new body elsewhere.