Artist Evan Hobart is a talent. His set of Skull Cities is a fantastic viewing experience. Speaking as a gamer and occassional GM I think this collection oozes inspiration and ideas.
Who might live in a skull city? Giant skulls or small houses? Imagine your brave heroes staggering into a woodland clearing only to discover themselves surrounded by skulls on spikes. Each skull is a city and from each city comes the angry drone of pixie warriors. Imagine a post-apocalyptic future, your survivors are scratching out a life among the ruins of a once great city as they make their way across it. Their scout observes that each lamp post on the street is decorated by one of these tiny but deadly cities.