In southern France you'll find plenty of evidence of the Roman influence and presence. A more beautiful one of those is Pont du Gard. It is a large aqueduct which led the water supply over the river Gard, and is part of a 50 km long pipe transporting water from Fontaines d'Eure to Nîmes. The nature and area is very beautiful and it's certainly a place worth visiting when you're in the region.
I was there on a beautiful day in June back in 2001. Just to lie on a rock at the riverbed and gaze into the air to see how the building rises over you is impressive. You can't help but wonder how the Romans could build such beautiful things which still stands strong two-thousand years later.
The aqueduct is 49 metres tall and 275 metres long at its greatest span. The river runs through a small canyon here and the sides are quite steep. You'll have to catch your breath again after climbing to the top of the aqueduct. The view is magnificent and if you have a bit of fear of heights, you'll feel the thrill. On the bottom level is a road which leads you over the river 22 metres up in the air.
The road has been used since the middle ages and in the eigthteenth century the bridge and road was expanded to stabilize the building. The place was a tourist attraction already back then. Pont du Gard was added to UNESCO's woldheritage list in 1985. Members of the maison guild in France still has to visit the aqueduct to this day as part of their education.
Official hompage: http://www.lepontdugard.com/