Rome built in stone here, and then the town grew on top of it. Bad Ems stands where the Lahn winds through a tight gorge, and the fort and the civil settlement beside it formed a small frontier community, with soldiers, traders and families living in the shadow of the Limes. The Roman fort is now buried beneath the modern town, so the site is more an idea than a sight, but the Limes trail in the woods above makes the story easy to follow, and the town museum helps with the details.
You arrive here by one of the best small river roads in the Rhineland. The Lahn valley road is a ribbon of gentle curves, with the water on one side and steep, forested slopes on the other. It is not fast, and it should not be, since the road is shared with cyclists and day trippers, but the rhythm is easy and the scenery changes every few minutes. If you want more, climb out of the valley on one of the side roads toward the Westerwald or the Taunus, where tighter bends and hairpins reward patience. Weekday mornings and shoulder seasons are best.
This is a very easy place to stop. With almost ten thousand residents, Bad Ems has fuel, bakeries and restaurants, and the long promenade along the river is a pleasant place to sit. The spa heritage is strong: the warm springs were used by the Romans and later by a stream of European aristocrats, and the Kurhaus and colonnades still carry that grand nineteenth-century manner. Tsar Alexander II took the cure here, and the Russian church built for his visits remains. In 1870 the telegram that became known as the Ems Dispatch was drafted here, and historians argue over how much it triggered the Franco-Prussian War.
Fachbach, across the river, is small but pleasant for a short stop. There is not much else to say except that a Roman soldier posted here in winter would have hated the cold and loved the baths.