The Schwedenschanzen are historically interesting as part of Lübeck's medieval Landwehr (information board on site, more on this, for example, here: de.wikipedia.org/wiki/Lübecker_Landgraben ). Since a path leads across the ramparts, …
The narrow path to the moor lake is somewhat hidden and you can quickly drive past it if you don't know it. It is currently blocked by some felled trees. …
A few steps away from the path and at reduced speed (i.e. not thundering through the heather at 20 km / h plus) you can admire the nature of the heather with heather and small trees ... :-)
The moat and some ramparts (especially the so-called Schwedenschanze in Lauerholz[1]) form the medieval land defense with which Lübeck, like other cities in the Middle Ages, secured its urban area.