Pem! That piece of ice shattered. Pum! A tyre flats on that car. Blam! The cameraman is gone. A child's imagination is matchless and undying - but images give back the faint hint of Porta Venezia, relic of the Spanish walls torn down at the end of the 19th Century, and the sorrounding traffic, while the streets get more and more crowded with modern and streamlined vehicles.