If I saw it correctly in todays stream, the Thuringian Forest and the Ore Mountains are impassable. Do we know why? I mean, I understand that parts of the alps are. Have these mountain ranges been historically obstacles qualifying as 'impassable'? And if so, why aren't the Harz, Black Forest and Bavarian Forest?
Edit: I noticed the Black Forest indeed is impassable, too.
Edit: I noticed the Black Forest indeed is impassable, too.