Sandopolis

Sandopolis is an extremely lengthy desert region in Sonic's dimension, stretching on for many miles; plagued by a hot sun and little to no oases, this sweltering desert is very difficult to traverse. Beneath the sand, however, is an elaborate egyptian-styled tomb, filled with many stone guardians; the tomb is prone to losing light, and so finds itself frequently inhabited by ghosts, as Sonic and Knuckles both discovered for themselves one day ("Sonic and Knuckles" / "Sonic 3 & Knuckles"). In the "Dimension" saga, both Sonic and Knuckles express their distaste at the fact that they must travel to Sandopolis once more to search for one of the missing sacred elements. Specifically, the wind element is sent here, and the alliance of heroes finds itself traveling many miles through the endless desert in search of it, almost to no avail. Sonic, Knuckles, Zim, and GIR accidentally sink into a patch of quicksand (much to Amy's despair), but this actually allows them to search the underground tomb for the element; eventually Mr. D, Treeby, and Tank appear and battle the group of four, but before long, they inadvertently cause massive amounts of sand to begin pouring in from above, filling the entire tomb. They all make their quick escape, but not before Sonic successfully finds and collects the wind element at last, prevailing over Mr. D with it. The convenient ladder leading back outside serves as the group's salvation, as they reunite with the rest of the alliance and make their escape from Sandopolis. Presumably, Mr. D punishes his two henchmen here, for letting their enemies get away.