Something about that is incredibly interesting to me. And for some reason it makes me sad:

You cannot fully understand even a city. It takes too much time -- as soon as you understand one piece, the other pieces have changed.

Cities are small, in the grand scheme of things. When it comes to larger things-- states, nations, planets, there's no way you could ever fully understand them. All you can get is a tiny, ephemeral snapshot, stuck in time.

It's humbling to think about, and I don't really know why it makes me sad.