City and urbanization

What is a city? What does it have to tell us? What distinguishes the contemporary complex or ultra-sophisticated city from other supposedly developing cities? In other almost identical terms what makes a metropolis if not a megalopolis the spectacle of urban power in its most formidable form the true portrait of an (over)urbanized space? To decide this it is essential to analyze the meaning of the term urbanization or what we can also call the urban fact. Currently it is in fact almost infallible it seems that the concept of the urbanization is not a ground unexplored in depth by different disciplines; so much it governs and shapes inexorably the existential framework of our life is attached to its mode of functioning and consequently becomes an implicative factor of any possible urban and human transmutation.