Flanking the borders of Austria and the Czech Republic, Passau dates back more than 2,500 years. Originally settled by the Celts, then by the Romans, it later passed into the possession of prince-bishops whose domains stretched into present-day Hungary. In 752 a monk named Boniface founded the diocese of Passau, which at its height would be the largest church subdivision in the entire Holy Roman Empire.
Passau's location is truly unique. Nowhere else in the world do three rivers—the Ilz from the north, the Danube from the west, and the Inn from the south—meet. Wedged between the Inn and the Danube, the Old Town is a maze of narrow cobblestone streets lined with beautifully preserved burgher and patrician houses and riddled with churches. Many streets have been closed to traffic, making the Old Town a fun and mysterious place to explore.