In the Middle Ages, the Dukes of Milan (the Visconti) built three castles in Bellinzona enabling them to defend the strategically placed town and control traffic passing through the valley and over the passes. The castles (Castelgrande, Castello di Montebello and Castello di Sasso Corbaro) were designated UNESCO World Heritage Sites in 2000.
After 1242, the Dukes of Milan rebuilt and enlarged the fortress again upon the foundation of the old Roman structure after they conquered the castle in support of the Pope.
Castelgrande’s main features are the Torre Bianca (White Tower) and the Torre Nera (Black Tower) joined by crenellated walls which encircle the inner baily.