The Great Crater is a prominent feature of the continent of Downunda in the southern hemisphere of Mobius. It is the original site of the Floating Island, which was removed from the continent in order to avoid the impending White Comet. Since then, the crater has served as a place for the Ancient Walkers and Athair to meet with Tails and Knuckles the Echidna, and also as a prison run by the evil Crocbot. (StH: #34, #48, #49, TMS: #2, #3) When Tails hypothesizes the Floating Island could return to the planet's surface by returning to the crater, Athair notes that the crater is in fact larger than the full diameter of the Floating Island, due to the impact of the White Comet destroying the original site.
Following Dr. Finitevus's alliance with the Platypus Dark Egg Legion, Angel Island was chained to the site via cannons surrounding the crater's rim while on it's routine flight path. The crater also served as the legion's base of operations until they were routed by the combined force of the Downunda Freedom Fighters and Chaotix and Angel Island was set free. (SU: #10, #11, #12)