One of the largest examples of Roman architecture north of the Alps can be found on the end of the Hotel Bischofshof am Dom in central Regensburg. This gate was one of the entrances leading from the Donau River (Danube) to the camp once known as Castra Regina. The gate dates from about 179 AD. One of the hotel’s suites is built right into the ancient gate. We had guests stay here in September.