This photo was taken under a bridge called "Brankov most" (Branko's bridge) in Belgrade. A tripod was mandatory, I used somewhat longer exposure, and I had my two ND filters on (ND4 + ND8). It was a dull, cloudy day, and the colors were terrible, so I opted for something which was going to look interesting in the grayscale.
During the post-processing, I lowered shadows and blacks, so none of the bridge details could be seen, only a black area. Looks like someone torn the photo in two pieces :). Further, I altered highlights and contrast a little bit, so I could emphasize the clouds.
I'd love to hear your feedback :)