I've done this matte painting in my spare time as an excercise, mainly to test a tecnique for painting clouds on different layers.
For the subject I have been inspired by the beautiful landscape of the Tuscan hills, and the magic ruins of the ancient Rome.

I've used Photoshop and Painter to paint the landscape (in 7531*3131 res.) on different layers and Combustion's 3D environment to recombine it in a sort of multiplane camera, in order to create a parallax effect.