REGENSBURG is located at the confluence of the Danube and Regen rivers. It is one of the oldest known settlements in Europe, dating from the stone age. Residents are proud of their stone bridge, which was built in the Twelfth Century. Regensburg wasn't damaged much in World War II, so many ancient buildings are still standing. Building began on Regensturg Cathedral, the Dom, in 1275. It wasn't completed until 1634. It is a fine example of Gothic architecture.