Regensburg (German pronunciation: ) is a city in Bavaria, Germany, at the confluence of the Danube and Regen River. To the east lies the Bavarian Forest. Regensburg is the capital of the Bavarian administrative region Upper Palatinate. The medieval centre of the city is a UNESCO World Heritage Site. Generally known in English as Ratisbon until well into the twentieth century. The city is known as Ratisbonne in French. The first settlements in Regensburg date to the Stone Age. The Celtic name Radasbona was the oldest name given to a settlement near the present city. Around AD 90, the Romans built a fort there. In 179, the Roman fort Castra Regina ("fortress by the river Regen") was built for Legio III Italica during the reign of Emperor Marcus Aurelius. It was an important camp on the most northern point of the Danube: it corresponds to what is today the core of Regensburg's Altstadt ("Old City") east of the Obere and Untere Bachgasse and West of the Schwanenplatz. It is believed that e...