For planning purposes: it can be a blisteringly hot part of the country, so please don't visit in high summer unless you love hordes of tourists and stifling heat that can make you rather light-headed. That said, do come; the area is vast and beautiful, and the bridge can make you dream.
The problem with being for all intents and purposes a local is that you become far too cool to go through local museums. It was only after looking at these photos I'd taken (then forgotten) that I realized I actually knew embarassingly little about the history of this part of the aqueduct that originally ran the fifty-some kilometers from Uzes to Nimes. So, rather belatedly, I went online to the official site (only in French, I'm afraid).
At nearly 50 m high, it is the highest known Roman aqueduct in the world. It crosses the river Gardon (which gave its name to the region, le Gard), and measures some 360 meters in length. On its first level, there is a wide road and at the top of the third level, a water conduit. The entire aqueduct had a gradient of 34 cm/km (1/3000), which meant it descended only 17 m vertically in its entire length...It is estimated that the aqueduct provided 20,000 cubic meters (5 million gallons) of spring water daily to Nimes, known under the Romans as Nemausus.
Visiting the Pont can bring to mind the Egyptian Pyramids; at least it did for me. This is because it was constructed entirely without the use of mortar, and because the Romans used (locally quarried) limestone, as did the Egyptians. The stones are enormous, mind you--some are 6 tons--and, as with the Pyramids, precision cut to fit perfectly together. According to Wikipedia:
The masonry was lifted into place by block and tackle with a massive human-powered treadmill providing the power for the winch. A complex scaffold was erected to support the aqueduct as it was being built. The face of the aqueduct still bears the mark of its construction, in the form of protruding scaffolding supports and ridges on the piers which supported the semicircular wooden frames on which the arches were constructed. It is believed to have taken about three years to build, employing between 800 and 1,000 workers.
Hmm. Maybe Sarah Palin was aiming for an Alaska version of this, before her ambition was thwarted. Maybe I am getting little light-headed myself and require some hydration. (Where's that mint lemonade when I need it?)
Update: the weekend edition (May 16-17) of the New York Times has a article about finding Roman Gaul in the south of France, and features a slide show, which offers, among other Roman images a gorgeous night shot of the Pont du Gard.