Cities have evolved in a very similar way to humans, both physically and philosophically. Both are centered around a core of very complex, and sometimes intangible systems. These systems are surround by the sub-systems which they depend on. These sub-systems are multiples of smaller, less complex systems. The fact that both have gradually evolved into what they are today, driven by the same mechanism of necessity, is a strange notion. Jimmy Tamborello says it best:
"Just don't forget, that it's dumb luck that got you here."