This is old news considering it opened in 2003, but I still found the story behind Germany’s Water bridge fascinating.

Engineers first dreamt of joining the two waterways as far back as 1919. Construction to bridge the Elbe river near Magdeburg actually started in the 1930s, but progress was halted during the Second World War in 1942. After the Cold War split Germany the project was shelved indefinitely, but things were put back on track following reunification in 1990.

Wikipedia entry.