This is a nice shot. I'd love to see, after the challenge, what it would look like with a bit of sharping, and some extra filters to keep the jaggies along the rooftops down (not sure if that can be accomplished in such dramatic lighting, though).
Knowing how it was taken from the validation statement, I think it's fairly well done... however, it's far too red, and that detracts from the Sepia effect.
Composition: Nice use of horz thirds.
Technical: Nice focus. Like the minimal shadows.
Meets challenge: Yes - sepia filter #005 I believe. ;-)
Overall impression: Looks a little too orange for me - but very resourceful with the filter. :-)
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I like the sky a lot, but he lighting on the ruins is dark and flat. Since the ruins are the subject I'd prefer to see the exposure, lighting, and color compliment them more. The whole picture feels very red.