This is the Lighthouse in Flügge on the island of Fehmarn (Germany). It’s located in the middle of the Baltic Sea. The island has a small connection to the landmass via a small bridge you can see in the left of the picture.
It’s a popular holiday resort and usually one of the sunniest places in Germany. When I took the picture it was a rather cloudy day and I managed to get a rare glimpse of sunlight.
This picture is a composite of two separate images. The original (uncropped) file size is 35,7 megapixels.