The Magdeburg Water Bridge

The Magdeburg Water Bridge is a navigable aqueduct in Germany that connects the Elbe-Havel Canal to the Mittelland Canal, and allows ships to cross over the Elbe River. At 918 meters, it is the longest navigable aqueduct in the world. 

The Elbe-Havel and Mittelland canals had previously met near Magdeburg but on opposite sides of the Elbe. Ships moving between the two had to make a 12-kilometer detour, descending from the Mittelland Canal through the Rothensee boat lift into the Elbe, then sailing downstream on the river, before entering the Elbe-Havel Canal through Niegripp lock. Low water levels in the Elbe often prevented fully laden canal barges from making this crossing, requiring time-consuming off-loading of cargo.

Construction of the water link was started as early as in the 1930s but due to the World War 2 and subsequent division of Germany the work remained suspended till 1997. The aqueduct was finally completed and opened to the public in 2003.