Pont du Gard

Three tiers of arches cross the gorge and the mathematics is visible in every joint — no mortar, no binding, just limestone blocks cut so precisely that gravity alone has held them for two millennia. The Pont du Gard stands in the Gardon gorge of southern France, the tallest bridge the Romans ever built, part of an aqueduct that carried spring water to Nîmes and still looks as if it could do it tomorrow.

The Pont du Gard was raised in the first century to carry the aqueduct of Nîmes across the Gardon — the water travelled some fifty kilometres from a spring near Uzès on a gradient so slight it can barely be measured — and its three tiers of arches rise almost fifty metres above the river, the huge blocks of the lower levels laid dry, without mortar, each cut to sit on its neighbour. It is the highest Roman aqueduct bridge in the world, World Heritage listed, and the visitor site around it holds a museum that makes the engineering tangible. Below, the Gardon runs green and slow through the gorge, and in summer people swim from the pebble beaches and rocks under the arches — the water is cold, the current can be strong after rain, and the site posts the conditions. Paths lead along both banks and up onto the garrigue for the view of the whole bridge against the hills.