Leonardo da Vinci is widely considered to be one of the most diversely gifted people ever to have lived. Among his many other talents, the 15th century polymath, who was court expert to the Duchy of Milan, designed fortifications. Historians from all over the world are now examining the theory that it was he who built the 'Rivellino', the ramparts of the castle in Locarno, in southern Switzerland. (SF/swissinfo)