Regensburg is a city in Bavaria, Germany, at the confluence of the Danube, Regen and Naab rivers. It's known for its well-preserved medieval core. Dominating the skyline is Regensburg Cathedral, a twin-spired Gothic landmark that’s home to the Regensburger Domspatzen choir. Nearby, the Altes Rathaus, a former royal palace of the Thurn und Taxis family, houses the Imperial Hall with its large fresco of Emperor Alexander I.