I made this project for CG Society Matte Painting challenge, the base plate was provided by David Luong, the forum moderator. I used several photos from shutterstock to make the retouching and achieve this look, and the entire image took a couple of weeks to finish. 
Hope you like this.
Cheers! 
Rafael Falconi
                    
                    landscape
                    collage
                    fantasy
                    background
                    retouching
                    history
                    montage
                    painting
                    matte
                    environment
                    concept
                    digital