Arrive in picturesque Passau this morning for a guided walking tour in this 2,000-year-old city, strategically situated at the confluence of three rivers - the Danube, Inn and Ilz. Walk through Old Town along its atmospheric cobblestone streets, graced with fine Gothic and Baroque architecture, and see the city’s ancient fortifications and handsome St. Stephan’s Cathedral, home to the largest organ in the world. Or, you can join an optional excursion to Salzburg, birthplace of Wolfgang Amadeus Mozart and the setting for the classic film, The Sound of Music. Those staying on board will enjoy an afternoon of scenic cruising to Linz, Austria. Meals B,L,D