Pont du Gard

To bring water to the Roman colony of Nemausus, modern Nîmes, an aqueduct was built from the Eure spring near Uzès. The two points are only about 20 km apart in a straight line, but the channel took a long detour around rough hills, and the Pont du Gard carried it over the river Gardon. Construction was long credited to Augustus's aide Agrippa around 19 BC, but newer excavations point to AD 40 to 60, and UNESCO dates it to the middle of the 1st century.

The bridge rises in three tiers of arches to 48.77 m. It holds an estimated 50,400 tonnes of limestone in blocks of up to 6 tonnes, most of it cut at a quarry about 700 m downstream, and was built largely without mortar. Maintenance lapsed from the 4th century, deposits clogged the channel, and the aqueduct seems to have gone out of use by about the 6th century.

The bridge survived because it went on serving as a toll bridge. In the 13th century the French king granted the lords of Uzès the right to levy tolls, and later the bishops of Uzès kept it in repair. In the 1620s Henri, Duke of Rohan, had one side of the second tier of arches cut back by about a third to let his artillery cross, and in 1743 to 1747 the engineer Henri Pitot added a road bridge alongside the lowest tier. Napoleon III visited in 1850 and backed a restoration carried out from 1855 to 1858, and the bridge was inscribed as a World Heritage site in 1985.