Thank you guys, thanks THX1138 
Just a little update on my entry... So I've been thinking about it for a while, and decided that I'll push it a bit back in time. I thought about the 1920s era at first because that's one of my favourites, and I can really image myself living at that time. And the detectives and noire stuff really was my favourite when I was young, so it's kind of a dream place for me - even though if it's a bit dusty and bad looking
But as I was thinking about it, I kept ending up in an other era, which I "discovered" 1-2 years ago, and really got engaged with it, and that's the era between 1880-1900, or the time of Sherlock Holmes So this is a bit of modification to my original subject, and I'm thinking about putting in some imaginary steampunk elements in it - thus making it a created world, and not staying in the boundaries of reality But I'm not sure about this yet...
And one last thing, I'm proceeding really slowly at this time, still trying to come up with the concept image - I'm thinking about making a drawing first that'll show what my general idea is.
reckon a some good prep work would be a good idea for this challenge, where artistic quality is cited in the judging criteria. attention to composition and a good working idea for your final outcome could come in very handy....