The theme concerns the changes applied to the landscape between the Middle Ages and Leonardo’s time, analysing both the hydraulic structures (springs, streams and weirs) and the lost city of Semifonte which, along with the Polish town of Sandomierz, is the object of a specific and innovative research project by ITABC-CNR, the Polish Academy of Science and the University of Florence. The virtual reconstructions allow us to observe the transformations of the medieval landscape, before and after the founding of Alberto’s city, up to its desctruction and the subsequent changes brought by the constitution of urban structures.