Here is an example of work with multiple layers ( 2 for abbey and 3 for skies ) and gradients. Some radiance filters, ( in very minor scale ) were used to create realistic blend between the skies and the abbey. All those damn tourists and bunch of decorated busses were taken away. This is what might happen when you mix Mexican skies with French landmarks, yet I am sure this would not be noticeable if I did not tell this :-)