Archaeological excavations in recent years have brought to light findings from ancient civilizations dating back to the Mycenaean years.

The existence of the ancient cities of Aigeira, Eliki, Aiges, Voura, Kyrenia, Aigio, Trapeza, as well as the findings from the excavations make Aegialia a center of great archaeological and historical interest. Aigeira, Eliki, and Aigio are mentioned by Homer as taking part in the Trojan War under Agamemnon. Ancient Eliki, our own Atlantis, that according to historical sources sank spontaneously into the sea after a very strong earthquake that struck the region of Aegialia in 373 BC. Pausanias reports that its ruins were visible at the bottom during his time.In the area of ​​ancient Eliki, in recent years, geo-archaeological excavations have been carried out that have brought to light findings mainly of the Early Helladic, Hellenistic and Roman eras. The Ancient Theater of Aigeira, one of the most important monuments in the area, has been fully unveiled and important restoration work has been done, which continues to this day. The first excavations began in 1916 under the Austrian archaeologist Otto Walter and the Austrian Archaeological Institute. Its construction dates back to the first half of the 3rd century BC, around 280-250 BC.It is carved for the most part on natural rock overlooking the Corinthian Gulf and geographically opposite Delphi.The theater is open to the public and during the summer season hosts a few selected cultural performances.