Outside of Nimes is the Pont du Gard, which spans the Gard river. It is part of a long aqueduct which was built around 19 B.c. to bring water from a spring down to Nimes. It is an amazing work of engineering in that the bridge was put together without the use of mortar.
Here you can see how the aqueduct was covered, as a part of the covering is gone on the right side
On the way in, there are these 3 really old olive trees. There was a plaque with them which explains how they were moved here from where they originally were growing and were over 100 years old.
There is one spot where people go swimming in the river under the bridge