The Cerna valley in south-western Romania has been a corridor for armies and travellers since antiquity. Between the Banat mountains and the Mehedinți plateau, the valley carried the Roman road from the Danube crossing at Drobeta northwards toward Tibiscum and the heart of Dacia. At Mehadia, the Romans built a fort known as Ad Mediam, and the remains called Praetorium or Zidină, meaning ruined walls, mark the site. The stone foundations are visible in places, and the site is one of the components of the Roman frontier in Dacia proposed for World Heritage status.
Eight kilometres away, Băile Herculane is one of the oldest spa towns in Europe. The Romans dedicated its hot springs to Hercules, and in the nineteenth century the Habsburgs turned it into a fashionable resort with grand hotels, baths and promenades. Many of those buildings are now crumbling, which gives the town a haunting atmosphere, but restoration efforts are underway. The spa still functions, and you can bathe in the thermal waters.
The Domogled–Valea Cernei national park surrounds the upper valley, with limestone cliffs, beech and black pine forests, and a rich population of butterflies, snakes and birds of prey. The road up the Cerna valley from Herculane is narrow and winding, with tunnels and rock walls, and becomes rougher as it climbs toward the source of the river. South of Mehadia, the main road leads to Orșova and the Danube gorges at the Iron Gates, one of the most spectacular river landscapes in Europe.
The DN6 through the valley is a main road, with trucks and fast traffic, so take care. Băile Herculane has fuel, restaurants and accommodation, and Orșova, on the Danube, is another good base. Bring a swimsuit if you want to try the open-air thermal pools along the river. Spring and autumn are the best times, when the forests are fresh or golden and the summer crowds have gone.