Pont du Gard (pôN dü gär) [key], Roman aqueduct across the Gard River, Gard dept., S France. Built in 19 B.C. to supply Nîmes with water, it consists of three tiers of arches and is c.900 ft (270 m) long and c.160 ft (50 m) high. This famous construction is admired for its architectural proportions. The lowest tier is now used as a road bridge.