Marcus Aurelius is said to have written part of his Meditations at Carnuntum, while campaigning against the Germanic tribes across the Danube in the second century. The city was then the capital of the Roman province of Upper Pannonia, a sprawling legionary fortress and civilian town of tens of thousands of people on the frontier of the empire. Today, the village of Petronell-Carnuntum sits on part of the site, and the archaeological park has reconstructed a Roman quarter with houses, baths and streets, built using ancient techniques, a remarkable way to imagine life on the frontier.
The most striking monument is the Heidentor, the heathens' gate, a massive ruined arch standing alone in the fields south of the village, built in the fourth century, possibly to commemorate a victory. It is a haunting sight, especially in the evening light. The amphitheatres and the museum in nearby Bad Deutsch-Altenburg complete the picture of a great Roman city.
The landscape here is the Danube floodplain, protected as the Donau-Auen National Park, one of the last large wetland forests in central Europe, with side arms, gravel banks and dense riparian woods. The riding is flat and relaxed, with roads along the river and through the fields and villages. Traffic can be heavy on the main road towards Bratislava, and wind is common on the open plain.
Fuel and food are most easily found in Hainburg an der Donau or Bruck an der Leitha. Hainburg has impressive medieval walls and gates and a castle ruin on the hill above the river. A visit to the Roman sites and a meal in a local Heuriger, a wine tavern, make a satisfying day. The Neusiedler See lies to the south.