Below are pieces that evoke a certain dark mood. Would be great to brew up a cup of hot coffee for enjoyment while posting these images.

I like the saturation of the sky and in the facade of this gothic cathedral. It was a cold day in Budapest, which adds a temperamental mood to the piece.
Considered one of the biggest ancient castles in the world according to the Guinness Book of Records, the Prague Castle stands tempestuously against an ominous sky. Its gothic angles and Romanesque interiors add a certain charm and mystery to the structure. I would love to start out a fairy-tale book with this scene as the introductory opening shot of a castle in the hills.