Bad Ems has been a spa town since the Romans noticed the springs, and today it is a handsome, slightly faded place squeezed into the narrow Lahn valley between wooded hills. The town and its surroundings sit on the line of the Upper Germanic Limes, which the Roman Empire pushed through here to protect the valley and its minerals. A fortlet and a watchtower were built on the heights above the river, and the remains give the numbered label its meaning. Walk a short way up and you can see why the soldiers picked the spot: the slopes drop sharply to the water, and the view along the valley is long.
The Lahn here is lovely riding country. The road along the river bends with the water and gives views of old railway viaducts, steep woods and the occasional castle on a crag. Up on the ridges the lanes are tighter and steeper, with hairpins that make a bike feel properly alive. Traffic is moderate on the main valley road, heavier on summer weekends when cyclists and tourists fill the riverside, so early starts help. The Rhine is only a few kilometres to the west, and the contrast between its busy shipping and the Lahn's quiet bends is striking.
Bad Ems is large enough, with nearly ten thousand people, to have fuel, restaurants and cafes without difficulty. It has an unexpected piece of diplomatic history, because in 1870 a telegram from the King of Prussia, edited by Bismarck and known as the Ems Dispatch, helped push France into the war with Prussia. The spa buildings still carry the elegance of the nineteenth century, when European royalty came to take the waters, and Tsar Alexander II and Kaiser Wilhelm I were among the visitors. Russian Orthodox church architecture still stands in the town as a reminder.
If you are riding up to the tower site, go slowly on the narrow forest lanes and watch for walkers, because the Limes trail is popular. Late afternoon, with sunlight raking through the beeches, is the best time.