There is no real evidence that this Roman monument was actually dedicated to Diana:it is more likely that it was part of the sanctuary area dedicated to Nemausus, the spring which gave Nimes its name.
Although much restored in parts, it is nevertheless an interesting and impressive site. You can still see the remains of the barrel-vauled roof, the niches for statues and even some of the roof decoration (some in situ, some displayed elsewhere). Make sure you look up under the remaining barrel-vaulting to see the rather lovely carvings (avoid the pigeons and their droppings!).
A 'must-see' if you are visiting the gardens (which themselves are a 'must-see' if you are visiting Nimes).


