I've been reading Italo Calvino's Invisible Cities for a few months now. In short vignettes, Marco Polo describes the cities of his travels to their emperor, Kublai Khan, who has never seen the cities and never will. The cities Polo describes may or not exist, or the stories he tells may be numerous descriptions of the same place. That's not the point, though: Calvin0's fictional Marco Polo demonstrates that cities - or places in general - exist primarily in our perceptions and imaginations.
If ten people were to describe modern-day Boston to Kublai Khan, the Khan would imagine ten separate cities. The St. Louis experienced by someone who arrives by a cab ride from the airport is completely different from the St. Louis experienced by a hitchhiker, which, in turn, is different from the city experienced by one who arrives by riverboat.
Environmentalism is all about being more perceptive about the world around us. Invisible Cities is about being more imaginative in how we create and interpret those perceptions.
It's an amazing, brilliant book, but one that is taking me ages to finish. I find that after finishing every 2-page description of one of the cities, I need to put the book down and think about it for a few days. On the other hand, I know that when I do finish it, I'll feel a sense of loss for not being able ever to read it again for the first time. Well done, Mr. Calvino.