What does dreaming of strange cities mean?

I often have dreams about visiting unfamiliar cities, which sometimes have familiar buildings or sections, but I always seem to know my way around. In one dream, there was a city with a kind of "sky subway" that ran between buildings. One of them was the building where I worked, and another ran right to a hotel where I lived. Last night, I was in a city that had a movie theater that was used as a kind of meeting place. I'd never seen the city, but I knew the way to the theater. What do these dreams symbolize, if anything at all? Why cities? Why don't I dream of idyllic country towns or suburbs? I was born in a suburb and I live in one now. Why am I dreaming of skyscrapers, subways, hotels, etc?