Civilizations developed along routes of communication. Historically, rivers have provided the ideal location for the growth of cities and commerce. With the expansion of industrial development, however, trade and traffic moved from river to road. Now hidden, urban rivers still flow beneath city streets. Caroline Bacle takes us on a tour to discover lost rivers like the Petite rivière of St-Pierre in Montreal, the Saw Mill River in New York State, the River Tyburn in London, and the Bova-Celato in Brescia.<%YOUTUBE=adqutN5zf3A%>