West of Klosterneuburg, on the right bank of the Danube (bridge), lies the little town of Tulln (177m/581ft; pop. 11,000), one of the oldest towns in Austria. It was the Roman naval base of Comagena and the Tulne of the "Nibelungenlied", where King Etzel (Attila) received Kriemhild. The twin-towered Gothic parish church of St Stephen has
preserved a beautiful Romanesque west door with figures of the Apostles. Adjoining the church stands the 11-sided Chapel of the Three Kings (1160); the charnel-house has a magnificent doorway.
Beyond Zwentendorf, on the right bank, with Austria's only nuclear power station (not in operation) lies Tulln, to which King Etzel (Attila) in the "Nibelungenlied" traveled to meet his bride Kriemhild; many years earlier it had been the Roman settlement of Comegena.