Would Hannibal have seen the Pont du Gard?

No, he missed it by about 270 years, though he probably passed very close to where it now stands.

• Hannibal came through in 218 BC. He crossed the Rhône somewhere between Avignon and Beaucaire, most likely near Roquemaure or Fourques. That’s only about 15–25 km from the Gardon gorge where the Pont du Gard stands.
• The Pont du Gard was built around 40–60 AD, probably under Claudius, as part of the aqueduct carrying water to Nîmes. People used to credit it to Agrippa around 19 BC, but even that is two centuries too late for Hannibal.
• The Romans weren’t even there yet. In Hannibal’s day this was Gaulish land belonging to the Volcae tribe, the same people who lined the far bank of the Rhône trying to stop his crossing. Rome didn’t take the region until about 121 BC.

So his elephants may have drunk from the Gardon river right where the bridge now stands, long before any Romans built anything there.

Here’s how that conversation might have gone:

The elephant: General, after all these rivers, couldn’t someone build us a bridge?
Hannibal: The Romans will build one right here someday. Three tiers tall.
The elephant: For elephants?
Hannibal: For water. Romans care more about their baths than about you.
The elephant: …I’m starting to see why you don’t like them.

Want to follow Hannibal’s march yourself? Try the game: Rome and the Second Punic War.