railway bridge over the Vistula in Warsaw, Poland

A card from the time of the Generalgouvernement Warschau set up by the Germans between 1915 and 1918. The 400+ metre bridge was, needless to say, destroyed in WW2 and rebuilt in the late 1940s. The mermaid seems to be a customised version of the one on the city's coat of arms, see below.