The Pont du Gard is an ancient Roman aqueduct that crosses the Gardon River in southern France. Located near the town of Vers-Pont-du-Gard, the bridge is part of the Nîmes aqueduct, a 50-kilometre (31 mi) system built in the first century AD to carry water from a spring at Uzès to the Roman colony of Nemausus (Nîmes). Because of the uneven terrain between the two points, the mostly underground aqueduct followed a long, winding route that called for a bridge across the gorge of the Gardon River. The Pont du Gard is the highest of all elevated Roman aqueducts, and, along with the Aqueduct of Segovia, one of the best preserved. It was added to UNESCO's list of World Heritage Sites in 1985 because of its historical importance.