The Taunus is the low, forested mountain range that closes in the north of the Frankfurt basin, and the Romans put their frontier along and over it. Here, near Glashütten, the line passes through high woodland at roughly four hundred metres above sea level, in an area that is cold and often foggy in winter. Towers 3/41 to 3/44 belong to the third section of the Upper German-Raetian Limes, the one that UNESCO recognised in 2005 together with the rest of the frontier. The Romans cleared a swathe through the forest, set up a palisade, and watched the open ground to the north, where tribes of the Chatti lived. The name Glashütten itself recalls glassmaking, once common in these forests because wood, sand and potash were all to hand.
The roads here are some of the best in the Frankfurt hinterland. From the town the B8 goes down to Königstein and the plain, while up above the Feldberg, the highest point in the Taunus at around 880 metres, a network of narrow lanes with decent asphalt offers long, easy bends and good visibility. Cars and cyclists crowd the Feldberg on dry Sundays, so if you can, come on a weekday. Early morning is gorgeous, with mist in the hollows and sun hitting the beech tops.
Walkers do the Limes trail through the woods, and you will see a line of mounds and a rebuilt tower at some places along the way. The Saalburg, the reconstructed Roman fort near Bad Homburg, is not far, and it is the best place to understand what these watchtowers were for. If the weather turns, Idstein to the north has a medieval centre with half-timbered houses and a witch tower. Look closely at the beams.
Glashütten and the neighbouring villages have enough people to keep a pump going, and Schmitten and Waldems both have fuel and bakeries. In winter the Taunus can hold ice on shaded corners long after the valley has thawed, and the Feldberg road sometimes closes for snow. Come in late spring or September, when the beech leaves are young or just starting to turn, and take a flask, because cafe stops are sparse between the villages.