This is where it all begins, or ends, depending on which way you are walking. At Rheinbrohl, on the east bank of the Rhine between Bonn and Koblenz, the Upper Germanic-Raetian Limes left the river and struck out across country, running more than five hundred kilometres to the Danube near Regensburg. The first watchtowers, numbered 1/1 and 1/2, stood here near the river, and the line can be followed into the hills from the edge of the village. The whole frontier is part of the UNESCO Frontiers of the Roman Empire, and Rheinbrohl has a modern museum, the RömerWelt, which brings the frontier to life with reconstructions, exhibits and hands-on activities.
The Rhine valley here is broad and gentle, with vineyards on the slopes, small towns along both banks and barges sliding past on the river. Bad Hönningen and Rheinbrohl face Bad Breisig across the water, linked by a ferry, and further south, at Andernach, a cold-water geyser erupts high into the air on a peninsula in the river, said to be the highest of its kind in the world.
The riding along the Rhine is scenic but busy, with heavy traffic on the main roads on both banks, frequent towns and speed limits. The real fun lies in the hills: east of the river, the Westerwald offers rolling roads through forests and small villages, and to the west, across the ferry, the Eifel and the Ahr valley have twisting roads, volcanic lakes and the Nürburgring, the legendary race track, within reach. Weekends bring many motorcyclists, and the police are attentive.
Bad Hönningen, about a kilometre away, has fuel, shops and cafés, and its thermal baths are a pleasant place to relax. Rheinbrohl has smaller shops, and Bad Breisig across the river has more. Local food includes Rhineland dishes like Reibekuchen, potato pancakes with apple sauce, and Sauerbraten, marinated pot roast, and the local wines from the Rhine and the Ahr.
Come in spring, when the vineyards turn green, or in autumn, when the grape harvest brings wine festivals to many towns. Walk up from the river to the line of the first towers, and look out over the Rhine, the natural frontier that the Romans relied on for so long, before following the line into the hills.