I hadn't noticed it before in the releases for 2006, but when I saw andi's pictures I immediately saw it as the sort of piece which could be on a hill overlooking a town, maybe the remains of a castle. That was it could even be used with a modern town in System-X.
Looking at Playmobil.de where it shows the back of the box as well as the front if you click the front, you get a good deal for your money, something I hadn't appreciated just from andi's review. Overall, I wonder if anyone has started collecting the Supersets as a theme in themselves?