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.
How to melt plastic bottles if you really needed to. Can be done in an oven or a double boiler over a fire. Can make mini green house panels, replacement pieces for broken glass in a pinch, arrow tips, etc... Milk jugs can be used too, but will not be clear.