The Altstadt is built on a rocky spur of land formed by the confluence of the Inn and the Danube. To best appreciate its setting, cross the Danube to the Veste Oberhaus, St. Georg Berg 125, a medieval Episcopal fortress towering over the town and the river. Note how arches join many of the houses, giving them a unity of appearance. As you view the town, you can sense that the architecture here is more closely allied to northern Italy and the Tyrolean Alps than to cities to the north. The fortress houses the Oberhaus Museum (tel. 0851/4933512; www.oberhausmuseum.de), a museum of regional history going back to medieval times. It's open March to November Monday to Friday 9am to 5pm, and Saturday and Sunday 10am to 6pm. Admission is 5€ for adults, 4€ for children, and 10€ for a family ticket. Take the shuttle bus to the castle from Rathausplatz

Dominating the town are the twin towers of the Dom (St. Stephen's Cathedral), Domplatz 9 (tel. 0851/39241; bus: City-Bus). The original Gothic plan is clear, despite its 17th-century reconstruction in grand baroque style. Its most unusual feature is the octagonal dome over the intersection of the nave and transept. The interior of the cathedral is mainly Italian baroque -- almost gaudy, with its many decorations and paintings. Of particular interest is the choir, which remains from the Gothic period. A newer addition is a huge organ with 17,974 pipes, said to be the largest church organ in the world, built in 1928 and placed in an 18th-century casing. Thirty-minute concerts are given May to October Monday to Saturday at noon; there's a second performance on Thursday at 7:30pm. The noon concerts cost 4€ for adults and 2€ for students and children 13 and under. The cost of the Thursday 7:30pm concert varies based on your seat, and runs 5€ to 8€ for adults, 5€ for children. The Dom is open Monday to Saturday 8 to 11am and 12:30 to 6pm. Admission is free.

Below the cathedral, on the bank of the Danube, are the Marktplatz and the 13th-century Rathaus, with a facade decorated with painted murals depicting the history of the town. Inside, the huge knights' hall contains two large 19th-century frescoes illustrating incidents from the legend of the Nibelungen. The Town Hall has a Glockenspiel in its tower that plays at 10:30am, 2, and 7:25pm; on Saturday there's an additional performance at 3pm.

Cruising the Danube

One reason for visiting this Dreiflüssestadt (town of three rivers) on the Austrian frontier is for a boat tour along the Danube and its tributaries, the Inn and the Ilz. Trips range from a 45-minute three-river tour to a steamer cruise downriver to Vienna. The cruises depart from Fritz-Schäffer Promenade. Many passengers prefer to go by boat, and then take a train back.

You may also be tempted to board one of the passenger ferries that makes runs (Apr-Oct only) practically every day from Passau downstream to the Austrian city of Linz. The trips take 5 hours downstream and 6 hours upstream, cost 23€ per person, and depart every day except Monday from the city's riverfront piers at 9am and noon.

If you're interested in gaining even greater insights into life along the Danube, you can continue by train from Linz to Vienna, buying a ferryboat, train, and hotel package priced at a reasonable 286€ per person, which will include round-trip transit by boat and train to Vienna, via Linz, from Passau, and 1 night's stay at a four-star hotel in Vienna. For information about either the day trip to Linz or the overnight sojourn in Vienna, contact the Donau-Schiffahrt Line (www.donauschiffahrt.de) through its local representative, Wurm & Köck, Höllgasse 26, D-94032 Passau (tel. 0851/929292).

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.