@Nicolaus_von_Kues If the pathfinding issue could only be solved - which appears to be quite complex - then we can define these features:
bridges, that block ships, allow passage of any civilians or troops, can be built up to a limited length, but also destroyed, e.g. by ships (also by whales?)
ramps (iirc there might exist historical evidences of this being used in siege tech) - can be built up to a limited height and destroyed
tunnels/portals/secret passageways (you discover an entrance and when entering it, reappear at another place on the map, must work in both directions, could start somewhere in a mountaineous area but never ends in or under a building). This needs to be defined when creating a map. Alternatively short passageways could be built by the player himself with a limited radius from his CC or fortress.transfer capacity shouold be limited though (cannot send a whole army through).
roads that have an accelerating aura for everyone, inlcuding enemies - pathfinding being particularly complex here as roads can be entered and left anywhere, as opposed to the other structures that have an entry point and an exit point.
Still brainstorming...