Regensburg, also Ratisbon, Ratisbona, is a city in Bavaria, Germany, located at the confluence of the Danube and Regen rivers, at the northernmost bend in the Danube. To the east lies the Bavarian Forest. Regensburg is the capital of the Bavarian administrative region Upper Palatinate. The large medieval center of the city is a UNESCO World Heritage Site. 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 small "cohort-fort" in what would now be the suburbs.