When the emperor Trajan wanted to invade Dacia for the second time, he told his engineer to build a bridge across the Danube, and the engineer, Apollodorus of Damascus, made it happen. The bridge at Drobeta, completed in 105 AD, was a marvel, with twenty stone piers carrying timber arches over a river that is more than a kilometre wide at this point, and for a thousand years it was the longest arch bridge in the world. It was built to move the legions across the river in one season, and it did its job. The wars that followed ended with the conquest of Dacia in 106 and the creation of a new Roman province.
Today you can see the remains on both banks, a stump of brick and stone at the Romanian end near the old fort, and a few piers that stick out of the water in dry summers. Trajan's Column in Rome shows the bridge in a carved relief, a long string of arches. The Iron Gates Region Museum, in Drobeta-Turnu Severin, houses a model of the bridge, as well as Roman finds, a ground plan of the fortress, and an exhibition on the Danube gorge.
The Danube is the real character of the place. Just upstream, the river squeezes into the gorge of the Iron Gates, which cuts through the Carpathians for about a hundred kilometres between Romania and Serbia, and the river runs deep and swift between steep, forested cliffs. The road along the northern bank, DN57 and DN6, is one of the best rides in the country, with views of the water, rock tunnels, and the colossal rock-carved face of Decebalus near Orsova, which is the tallest rock sculpture in Europe, completed in 2004. Traffic can be heavy on the main road with lorries, but the shoreline stretch is a joy on a clear morning. Spring and autumn are the best seasons, with soft light on the water, and the summer can be hot and busy.
With over a hundred thousand people, Drobeta-Turnu Severin has fuel, restaurants and hotels in plenty, and Simian, a few kilometres away, is a suburban town. Try a plate of grilled Danube fish, and a glass of local red wine, and take time to wander the park around the ruins at dusk, when the river turns pink.