Bellinzona’s castles are considered amongst the finest examples of medieval fortification architecture in Switzerland. Since 2000 they have been listed as a UNESCO World Heritage site. As they appear today, the fortifications, whose origins actually go much further back to a prehistoric settlement on Castel Grande hill, are mainly the result of intensive and complex building activity instigated by the Dukes of Milan in the 15th century. The construction of powerful defence installations which formed a barrage across the whole of the Ticino Valley floor to halt the advance of the confederates dates back to this period in history. Right up to the present day, these fortifications, with their battlements, towers and gates, continue to be a source of wonder and fascination.