The Frische Grube is one of the oldest artificial watercourses in Germany that run through a city. It connects Lake Schwerin with the Baltic Sea via the Mühlenteich, the Wallensteingraben and Lake Losten.
Created in the middle of the 13th century, using field stones, the pit served for a long time as a drinking and service water supply for the townspeople. Its water drove mill wheels and was a reservoir of fire-fighting water.