There's a bridge in Vienna hardly ever used for anything. It's closed for cars and even bikes and pedestrians. The bridge is leading to a power station and I guess that at least sometimes some vehicles will use it, otherwise why bother building it in the first place?
There might be and unusual answer to that one: probably some architect thought there was too much unused space which should be filled with a beautiful bridge.
Of course it seems rather unlikely that this would be so. But let's just enjoy imagining this being the case - for the bridge to Freudenau power station reaching over the locks of Freudenau dam:
