The weather was lovely, but the walk around Flakensee for the most part completely uninsteresting. The area around Woltersdorfer Schleuse is quite nice with many cafés and restaurants and an icecream parlor, and from there in the direction back to Erkner, for a couple of kilometers, it is possible to walk through forest along the lake, but the rest is inaccessible to the public, like so many waterfronts in Berlin and Brandenburg, because people living there have fenced off their property all the way. And there is A LOT of waterfronts in Berlin and Brandenburg. The fact that most of them are inaccessible to the public is a disgrace and that it goes unpunished utterly mind-boggling.
Here the link to the route on mapmywalk. Including the walks to and from SBH Jannowitzbrücke, Max and I walked about 13 km. Not our finest result for a Sunday, but not too shabby either :-).
A couple of photos taken with my smartphone. One of them of the quaint old tram still in use between Rahnsdorf and Woltersdorfer Schleuse.