I've been messing around with perspective a bit lately.  This is a study in two point I did.  It's a dark sci-fi city.  Building it absorbed all the planets resources, so anyone outside the city lives poor lives, not to mention the wildlife which is mostly extinct.  Since there isn't anywhere else to live the buildings have to keep getting taller to keep up with the population and eventually a stabilizing mechanism was created that allowed building parts to float to keep from falling over.