The Pont du Gard is an ancient Roman aqueduct that crosses the Gardon River in the south of France. A masterpiece of ancient architecture, it was added to UNESCO's list of World Heritage Sites in 1985 because of its historical and architectural importance. The bridge has three tiers of arches, standing 48.8m high, and once carried an estimated 200,000 cubic meters of water a day to the fountains, baths and homes of the citizens of Nîmes.