Aqueduc romain du Gier - site du Plat de l'Air

Chaponost

On the way out of Chaponost, the road opens onto a vision of Italy: a procession of stone and brick arches marching straight across the fields, towards Lyon glimpsed in the distance. This is the Gier aqueduct, the longest and most sophisticated of the four aqueducts that supplied water to Lugdunum, capital of the Gauls: 86 kilometres from the springs of the Gier, at the foot of Mont Pilat, to the Fourvière hill. Built in the 2nd century AD, the structure gathered together a string of feats: tunnels, bridges, and above all these inverted siphons where water, enclosed in lead pipes, plunged down one slope to climb back up the other — a hydraulic tour de force that still leaves engineers full of admiration. At Le Plat de l'Air, 72 of the original 92 arches still stand: a 550-metre run, the longest series of aqueduct arches visible in France, listed as a historic monument as early as 1900. The reticulated wall, that chequerboard of small diamond-shaped stones typical of Roman building sites, can be read here like an open book. The site, freely accessible, lends itself to a stroll at sunset, when the low light sets the brick aglow; guided tours recount the epic story of Lyon's water supply, from the catchment in the Pilat to the fountains of the upper town. Following the signposts, one finds other sections of the aqueduct in the surrounding countryside — a walk in the footsteps of Rome's water engineers, at the gates of Lyon.

Getting there : 11 route des Pins, 69630 Chaponost, at the place known as Le Plat de l'Air (GPS coordinates for the site). Free access all year; car park, picnic area, accessible paths. Guided tours all year by booking through the Monts du Lyonnais tourist office (04 82 90 10 85).

Opening times and access details are given as a guide only: check before you set out.

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