Barbegal aqueduct and mills, Roman archaeological site in Fontvieille, France

The Barbegal aqueduct and mills comprise 16 overshot water wheels arranged in two parallel sets of eight on a steep hillside, fed by two aqueducts from the Alpilles. The complex measures 61 metres long and 20 metres wide, with a central staircase separating the two rows. Substantial masonry remains of the water channels and mill foundations survive, along with a rock-hewn cleft at the top.

Built in the early 2nd century AD, the complex was fed by two aqueducts from the Alpilles that joined just north of the site, where a sluice controlled the flow. It operated until the early 3rd century, about a hundred years. The Arles aqueduct was partly listed as a monument historique on 12 July 1886, with further parts inscribed on 5 February 1937.

The site demonstrates how Roman engineers harnessed water to produce flour at an industrial scale for an entire city. This practical approach later inspired medieval monks and shaped how Europeans understood water power in manufacturing.

The site lies 12 km east northeast of Arles, near Fontvieille, where the Route de L'Aqueduc crosses the aqueduct remains; park there. Walk about 250 m south along the partly standing aqueduct, through a 3 m deep rock-cut cleft, to the top of the mill complex. The site is signposted as "Roman aqueduct", not as a mill, and was slightly overgrown in spring 2022, so take care on the ruins.

A 2018 study of calcium deposits on the paddle wheels suggests the flour was not mainly for Arles: it went into large batches of bread baked for ships. The site is signposted only as "Roman aqueduct", so the mill itself is easy to miss.