The so-called exedra of Herodes Atticus (which answers in all respects to a nymphaeum in the Roman style), the nymphaeum in the palace of Domitian and those in the villa of Hadrian at Tibur (five in number) may be specially mentioned.
The people were delighted by the removal of the imperial exedra (a large chamber with open front) in the circus, whereby five thousand additional places were provided.
The Exedra of Herodes Atticus stood at the north limit of the Altis, close to the north-east angle of the Heraeum, and immediately west of the westernmost treasure-house (that of Sicyon).
The exedra must have been seen by Pausanias, but he does not mention it.
The large basin of drinking-water in front of the exedra was fed thence, and served to associate the name of Herodes with a benefit of the highest practical value.
Very little was done in 1913-4; the " temple of Apollo Clarius " was found to be an exedra and a propylaea, and an oracular grotto of the god was discovered in the hills.
From these side-valleys water was now conducted to Olympia, entering the Altis at its north-east corner by an arched canal which passed behind the treasure-houses to the reservoir at the back of the exedra.