In our trip to France we have seen the Roman Pont du Gard, a part of the aqueduct that brought water by a 50 km long canal to the castellum divisorium of Nîmes, in the Narbonnaise region, from a spring near Uzès. To achieve an average of 34 cm par one km it follows sinuous pats or traverses the rock layer with galleries or is elevated on to walls or arches or bridges. The Pont du Gard goes over the deep valley of the river Gardon; it was constructed in 19 for order of Agrippa. It’s 49 m high and has three storeys: the first (142 m long) has six 22 m high arches and was used in Medieval times like a bridge, the second 8142 m long) eleven 20 m high arches and the last (275 m long), where runs the canal, thirty-five 7 m high arches. There was also adaptations of the devastating course of the river and the lips on the piers, the curved layout of the aqueduct and the opening of the main lower arch are designed to resist to the floods. The acqueduct use at the two lower levels stone blocks, that can weight up to six tons, and at the upper levels small stone rubble which hold the abuting flagstones of the canal.
The acqueduct is one of the most beautiful places I have ever seen because of its impresivenesse and its incredible technique of consctruction; it's absolutely worth to be visit - you must park 500 m from it. It justifies the inscription also as the nicest Roman acqueduct in the world, one of the few incribed on the WHL, and the best exression of Romans' technique, but I think that also other Roman monuments in Provence (like that in Nîmes or Saint-Rémy-de-Provence) could be inscibed alone or together with one, two or all of the WHS of Arles, Orange and Pont du Gard.