Nettelgraben

The Nettelgraben in the Schorfheide-Chorin Biosphere Reserve is a true biotope for reptiles and amphibians.

The approximately five kilometer long moat was dug by the monks in the 13th century to supply water to the Chorin monastery. At that time it connected the Choriner See with the higher situated White Lake.

The Nettelgraben is a beautiful, deep trench with very beautiful views.
The Nettelgraben is an artificial waterway in the Brandenburg district of Barnim and is located in the Schorfheide-Chorin biosphere reserve. The nearly five-kilometer-long ditch forms the only outflow of the Parsteiner See and connects it with the Ragöse (Ragöser Fließ) via the Weißen See and the Choriner Amtssee.
The moat was dug in the 13th century by the monks of the Cistercian monastery in Chorin, as the ragose runoff from the Choriner See (now the Amtssee) did not supply enough water to operate the monastery mills and to supply the monastery, which is located directly on the lake. The monastery brothers achieved the necessary water supply with the construction of the Nettelgraben from the Choriner See to the higher and now isolated White See, which at the time of construction in the 13th century formed a bay of the Parsteiner See. (Wikipedia)

Great hiking trail right next to the river (Nettelgraben).