Pont du Gard

The Pont du Gard, located near Vers-Pont-du-Gard in the Gard department, is the highest surviving Roman aqueduct bridge in the world and one of the most visited ancient monuments in France. Built in the mid-1st century CE, attributed to the engineering oversight of Marcus Agrippa, it formed part of a 50-kilometre aqueduct system supplying the Roman colony of Nemausus (modern Nîmes) with fresh water from springs near Uzès. The aqueduct delivered an estimated 40,000 cubic metres of water per day — enough to supply a city of 50,000 people. The bridge rises in three tiers to a height of 48.8 metres above the Gardon River. The lowest tier carries a Roman road across six large arches spanning the valley floor. The middle tier carries eleven arches of similar dimension directly above. The upper and narrowest tier carries the enclosed water channel (specus) on 35 small arches, running at a gradient so precise — dropping just 17 metres across the entire 50-kilometre system — that Roman engineers achieved it without mechanical instruments, relying on surveying rods and water levels. The stones, some weighing up to 6 tonnes, were fitted without mortar, held by iron clamps and the geometry of the arch. The aqueduct was in use until the 4th or 5th century CE, when declining maintenance led to calcite encrustation blocking the channel. The bridge itself survived largely because it was converted to a toll crossing for river traffic in the medieval period, generating revenue that prevented demolition. An 18th-century pedestrian walkway was added alongside the lower tier by order of local authorities. Systematic restoration began under Napoleon III in the 1850s. The modern site encompasses both the ancient bridge and a large visitor complex on the left bank, including an interactive museum on Roman aqueduct engineering and daily life, kayak hire on the Gardon below the bridge, and marked walking trails along the original aqueduct channel upstream through the garrigue scrubland. The Pont du Gard is a UNESCO World Heritage Site inscribed in 1985.