Photo montage and painting overlay.
I would just notice that the taxi on the left looks like it's moving, probably because of some slight wind effect coming from your texture work. Apart from that, this all picture is among the best and most realistic apocalyptic picture I've seen on DeviantArt. The water coming from the ground, the collapsed building on the right and the fire at the top, this all is well thought and draws something very credible.
Great work! xD