Werthausen sits on the left bank of the Rhine in Duisburg, across the river from the steelworks, harbour cranes and bridges of one of Europe's great industrial cities. It is an unexpected place to look for Rome, but the Lower Rhine was the frontier of the Roman Empire for centuries, and the line of forts, fortlets and watch posts along it is now inscribed on the UNESCO list as the Frontiers of the Roman Empire, the Lower German Limes. The site at Werthausen is one of these components, part of the chain of military posts that watched the river between the legionary bases at Neuss and Xanten.
The Rhine has shifted its course many times since Roman days, so the site lies in a landscape of old river arms, meadows and dykes. On the ground there is very little to see, and the interest lies in imagining the river as a defended border, with patrol boats on the water and Germanic tribes on the far bank. Nearby, at Moers-Asberg, the Roman fort of Asciburgium was one of the earliest on the Lower Rhine.
Duisburg itself is worth a look on its own merits. The Landschaftspark Duisburg-Nord, a former ironworks turned into a park, is one of the best examples of industrial heritage in Germany, and you can climb the blast furnace for a view over the Ruhr. The inland harbour is said to be the largest in Europe, and a boat trip there shows the scale of it. For food, the Ruhr's culture of currywurst and simple pubs is alive and well.
For riders, the area is flat and built-up, with heavy traffic, frequent lights and many speed cameras. The rewards come along the Rhine dykes and the small roads heading north toward Xanten, where the countryside opens into meadows, willows and big skies. Fuel and services are everywhere. Ride early on a Sunday morning to see the river at its quietest, with mist over the meadows and barges sliding past.