A few kilometres downstream from Melk, on the right bank of the Danube, Schloss Schönbühel occupies a similar rocky promontory to the abbey. The castle dates to the twelfth century and was rebuilt in its current form in the early nineteenth century; it is privately owned and not open to the public, but the view of it rising above the river — particularly from the water if you're travelling by boat — is one of the memorable images of the Wachau.
It appears frequently on postcards of the Wachau Valley alongside Dürnstein and Aggstein, and cycling or boating past it on the way between Melk and Krems is the natural way to appreciate it. The nearby ruins of Aggstein Castle, a few kilometres further downstream, are accessible on foot and offer panoramic views over the river.