Louros River & Roman Aqueduct (Agios Georgios)

The Louros is about 80 km long. It rises below Mount Tomaros in the Ioannina region and runs south through a narrow gorge and past Filippiada. It ends in the marshes and delta at the north of the Ambracian Gulf. It is one of only two rivers in the world where the critically endangered Greek lamprey has been found.

At Agios Georgios, below the hydroelectric dam, rich springs feed the river. They still supply drinking water to Preveza, Arta and Lefkada. Local legend says the water once poured out of a dark cave, the "Dragon's Hole", which now lies under the village church of Saint George.

The Romans tapped these springs to supply Nikopolis. Their aqueduct ran for about 45–50 km. It crossed the river on arched bridges, cut through a hill in a rock tunnel and followed channels across the plain, past Stefani and Archangelos, to the Nymphaeum of Nikopolis. Its piers are about 3.8 × 3.6 m and are strengthened with buttresses. Rows of them, some still joined by arches, stand by the river at Agios Georgios, the most impressive surviving stretch. Remains are also preserved at Rizovouni and Archangelos. Scholars disagree on when it was finished: anywhere from around the turn of the era to the late 2nd century AD.