On the site of Dodona, a sanctuary existed already in the IIth millennium BC. An oracle spoke there by the way of rustles in the foliage of an holy oak that the Selles (priests) translated into predictions.
The theatre, currently in restoration (2008), is one of largest of Greece with its 130 m diameter. It dates from the IIIth BC.
There remain the vestiges of the sanctuary dedicated to Zeus.
Photos from the sanctuary of Dodona
The ancient theatre of Dodona
Ruins of the sanctuary of Zeus Naios, where was the holy tree, cult places dedicated to Hercules, Dione, ... temple of Aphrodite. Near, the rests of a byzantine basilica - VIth AC.