Eider Canal conservation areas. Eider Canal The Eider Canal (also called the Schleswig-Holstein Canal) was an artificial waterway in southern Denmark (later northern Germany) which connected the North Sea with the Baltic Sea by way of the rivers Eider and Levensau. Constructed between 1777 and 1784, the Eider Canal was built to create a path for ships entering and exiting the Baltic that was shorter and less storm-prone than navigating around the Jutland peninsula. In the 1880s the canal was replaced by the enlarged Kiel Canal, which includes some of the Eider Canal's watercourse. The canal's watercourse followed the border between the
White Sea–Baltic Canal Bay near Megostrov Island; it was later captured by Finnish troops. On December 5, 1941, Finnish troops entered Medvezhyegorsk. On December 6, 1941, in a -37 °C frost, Finnish troops captured Povenets, the southern entrance to the White Sea–Baltic Canal. On the same day, Soviet troops started demolishing canal structures. Lock No. 1 was the first to be blown up. By the morning of December 8, Locks No 1 to 6, and dams No. 4 and 20 had all been demolished. At the same time heavy fighting took place in the area of the Povenets Lock Ladder (Locks No. 1