Passau's known as the City of Three Rivers, since it's where the Danube, the Inn and the Ilz all meet. Each one is a slightly different colour, so it's worth having a go at trying to spot which one's which. Your in-the-know guide will set a course for the Altstadt – or old town – where Italian-inspired buildings are strung together by criss-crossing cobbled streets. The whole lot's only a short walk from the port, too, so you won't have to venture far. As you plod through the centre, you'll see Baroque-designed St Stephen's Cathedral. You'll see the 13th-century Veste Oberhaus across the water, and a stroll along Hollgasse, or Artist's Alley, shows off Passau's flamboyant side.