Hmm... [ Qubit pauses for a second and taps his mouth, thinking. ] There's some stiff competition, but I have to go with Dimension Aqirax. The whole place is an acid swamp. Everything's corrosive. The ground, the giant mushrooms, especially the water. Fascinating experience, though, in hindsight - I'd never have expected megafauna to evolve in such a low-pH environment.