I've been playing with some terrain transformations, and found that some wouldn't work. I'd like to see if anyone else has had the same difficulty, and whether there are others that do work besides the ones I've noted. The following list gives transformation paths I've tried. Ones that worked are highlighted with an asterisk (*). Interestingly, I haven't seen some work that are actually put in the game as defaults (such as Marsh -> Coast). That seems wrong. Pollution transition changes (due to global warming): *Jungle revert to base terrain *Forest revert to base terrain Plains -> Desert Tundra -> Grassland -> Coast Grassland -> Coast Grassland -> Plains Marsh -> Coast Sea -> Coast Coast -> Plains Ocean -> Hills *Hills -> Mountains *Mountains -> Volcano Please add to this list if you've found others that work. I'm also interested in whether there are limitation that I'm not aware of (such as water is not allowed to transform).