According to the photographer:
This picture was taken in Beilstein by the river Mosel in Germany. It was one of the most famous of the small old towns situated there. The image was made of several vertical photographs processed into a panorama. This view represents the typical summer weather and climate in that region which is famous for its wines.
In the US we call this kind of deep river curve an oxbow. One of the most famous American oxbows has already been featured in a Wallpaper Monday.
(Click the image to curvate.)