It might be a matte painting, im not sure.. I combined a ton of images and didnt paint on it very much, mostly just clonestamp and some shadow/light painting.
Anyway, here are the pictures i used:
(i lowered their resolutions and cropped the parts i used)
3 of them are made by me, the others are from Google Imagesearch.
Took about 10 hours or so to make, its my first so im not very fast yet.. Only photoshop.