A UNESCO World Heritage site, the three magnificent castles of Bellinzona and their connecting walls are the only examples of defensive military architecture dating back to the Middle Ages that still exist in the Alpine region. We start from the most imposing castle, Castelgrande, to discover its importance and the strategic reason for its position. We continue on foot uphill to Montebello Castle, evocative and very particular from an architectural point of view. Walking uphill some more, we reach Sasso Corbaro, the smallest of the three castles, whose mass dominates the Bellinzona plain between the mountains and Lake Maggiore. We then walk back down into the historic town center. This tour is suitable for active people who are accustomed to walking uphill. Proper hiking attire and shoes are required. The tour can be modified for families with children, with a ride on the Artù Tourist Train.