This image is part of the Infinite OZ experience - "An artistic collaboration that brings to life the world of the Sci-Fi miniseries event, Tin Man." It is best understood by visiting the "experience" itself at:

http://www.scifi.com/tinman/oz/

The following artists also contributed: Philip Straub, Greg Petchkovsky, Martin Lisec, Gerardo de Gerard, Geoffrey White, Raphael Lacoste, Phil McDarby and Rudolf Herczog. The coordination and final animation was done by B-Reel.
The image was almost completely painted in Photoshop. Based on an initial sketch I used 3d Studio Max to make a quick mock-up model over which I would paint the final image. It was done over several weeks and the final image is about 10000 pixels wide (as are all the others) to allow for the big zoom. Each of the artists was given a short brief about the environment to create but the rest was up to us using our imagination and interpretation. I am quite proud to have been part of such an amazing group of artists.

Here is the initial sketch:

The 3d mockup:

And some details: