I try to leave my comments to PMs, so as not to clutter my galleries with my thoughts, but, in this case, an exception is warranted. : ) The pic is from Red Rock Canyon just outside of Las Vegas, as is the preceding pic. No polarizer or special processing was used -- the sky just came out that way from my usual editing process. In fact, all editing performed on the image was done to the whole of the image -- no selective editing. A fullsize version of the image is posted in the 16-35 / 2.8L lens test gallery.
I like how the use of the rock and scattered scrub in the framing add a sense depth. And the twi whiter puff clouds add an interesting dimension in what appears to be a lightly polarized shot. You can correct me if I'm wrong but either way I like it. Especially the chosen use of foreground elements.