For those of you of an enquiring turn of mind, visible in this painting are: Central City, Gigalopolis, Yellow Desert, Sand Ocean, Hidden Base, Pumpkin Hill, Dry Lagoon, Wild Canyon, Marble Zone, Sky Rail, Tails' Workshop, Spring Yard Zone, Green Hill, Neo Green Hill, Emerald Town, Starlight City, Scrap Brain, Prison Island, and various… other places, which I forget.
Sonic Geography is very non-constant so there was a good deal of creative interpretation involved to get so many things into one place.
The gigantic, smoking caldera down in the bottom-left is a location that has appeared over the course of the RP itself. We have dubbed it 'Mighty Mist Zone'. Apart from featuring very early in one plotline it is almost completely incidental.
It was made for the RP website itself, so please do not steal if you can possibly help it.