Berlin S-Bahn wanderer map, 1938

As those who have been there know, the urban area of Berlin covers a lot of territory that contains plenty of green areas.  This pre-war map was intended as a guide to wanderers i.e hikers, to forests and other excursion destinations that could be reached on the S-Bahn or city railway system.  An overview map of the present system from wikimedia is below; not all of this existed in 1938.