It was done a few summers ago - before I fully refined all my Photoshop techniques. I wish I could say I took the original photograph, but it was actually the second image I found on Google (hope no one minds...) But I mostly used the Clone Tool to paint the sky over the original structures. I then placed a high-contrast image of the Eiffel Tower in each spot where it belongs. I shrunk and lowered the opacity for those that were further away to enhance the illusion of perspective. I also increased the contrast to get a slightly more dramatic sunset. It was just for fun, and was my desktop background for a while.