DWM Shooting Range Bullet Trap

Even if it's really close to the border. Since the Landgraben clearly marks the border, this is definitely NOT in the territory of the former GDR!
It is probably an even older testimony to another dark era in German history:
From 1934 onwards, the DWM (German Weapons and Ammunition Factories) set up shooting ranges up to 1.9 km long in Lübeck to test the effectiveness of their ammunition. [Jungbluth, R., The Quandts: Germany's most successful entrepreneurial family, Campus Verlag, 2015]
Private Internet sources suggested (the sites in question no longer exist) that it was the bullet trap of the large shooting range.

At least it's not an old piece of the border!

Hidden in the middle of the forest, you suddenly come across the remains of a firing range of the former DWM ammunition factory, which was already here before the inner-German border.