The incredible Magdeburg Water Bridge in Germany is a navigable aqueduct 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 in the 1930s but due to World War 2 and the subsequent division of Germany the work remained suspended until 1997. The aqueduct was finally completed and opened to the public in 2003. Six years, 500 million euros, 918 meters long ... now this is engineering!
Here's one for all you armchair engineers and physicists:
Question: Did that bridge have to be designed to withstand the additional weight of ship and barge traffic, or just the weight of the water?
Answer: It only needs to be designed to withstand the weight of the water! Why? A ship always displaces an amount of water that weighs the same as the ship, regardless of how heavily a ship may be loaded.
