Minden Aqueduct

They are trough bridges. The water of the Mittelland Canal is in the trough of the bridge and ships can sail unhindered across the Weser. The Weser is connected to the canal with locks. The concrete trough bridge from 1914 was blown up by retreating German troops at the end of World War II. In 1949 the reinforced concrete bridge was put into operation. Since the dimensions of the old bridge became too small for the larger ships, a new steel trough bridge was built between 1993 and 1998 to the north as a supplement to the old trough bridge.

The waterway cross in Minden (Weser and Mittelland Canal) is very interesting and an engineering masterpiece.
de.wikipedia.org/wiki/Wasserstra%C3%9Fenkreuz_Minden

The Wasserstrassenkreuz is a gigantic structure. A mighty trough over the broad Weser valley.