A of the excavations at Helike. Drekis, Wikimedia Commons

Excerpt from popular-archaeology.com
A team of scholars and students will return to explore and investigate the site now thought to be the remains of the city of Helike, the legendary city that was for centuries the stuff of ancient writers and a tantalizing mystery for explorers and scientists for over 2,000 years. 

Archaeologists Uncovering Legendary Lost City of Poseidon
Ancient coin from the lost city of Poseidon

Led by Dr. Dora Katsonopoulou, Director of the Helike Society, researchers have uncovered a wealth of artifacts and structural remains dating from the Bronze Age through the Roman and Byzantine periods at sites near the southwest of the Gulf of Corinth in northern Peloponnesos. In 2000 and 2001, the research team in this area what is now thought to be the remains of ancient Helike, on the coastal plain between the Selinous and Kerynites Rivers. Excavation of trenches revealed the architectural remains of Classical period buildings at a depth of 3 m, likely destroyed by an earthquake and subsequently buried under the deposits of a shallow inland lagoon. “Thus the city did not sink into the depths of the Corinthian Gulf, as previously ”, reported the researchers, “but was submerged by an inland lagoon, which later silted over”. The excavations also uncovered a rich array of artifacts.

Ancient coin from the lost city of Poseidon

Also nearby, researchers uncovered evidence of an extensive and remarkably well-preserved Early Helladic coastal settlement (ca. 2600-2300 BC). This site is about 1 kilometer from the present shore, with remains at a depth of 3 to 5 meters below the . Finds included the foundations of a corridor house and other buildings that lined cobbled streets, along with abundant pottery. Luxury items found at the site, which included small gold and silver ornaments, have given clues about the apparent wealth of this period city. Additionally, sediments covering the Early Bronze Age city contained marine and lagoon microfauna, indicating that the ancient city was submerged in seawater for a period of time. A wall of one building was clearly offset in a way that strongly suggests the result of seismic activity, indicating that this early settlement may have also been destroyed and submerged by an earthquake, about 2,000 years before the famous earthquake that destroyed classical Helike in 373/372 B.C.  

It was this 4th century earthquake that struck the southwest shore of the Gulf of Corinth and destroyed the Classical city of Helike, purportedly submerging it into the sea. According to the literature, Helike, which became the principal city of Achaea, was founded in the Mycenaean period by Ion, the leader of the Ionian race. Helike subsequently became the capital of the Twelve Cities of ancient Achaea. The city area was anciently considered the location of the sanctuary of Poseidon, god of the sea and earthquakes. It was widely discussed in literature by many ancient Greek and Roman writers and visitors such as Strabo, Pausanias, Diodoris, Aelian and Ovid, and has been suggested by some scholars to be the inspiration for the story of Atlantis. But, like Atlantis, the actual whereabouts and evidence of Helike’s remains have eluded scholars and explorers for 2,000 years.  

It was not until 1988 that efforts began to bear fruit, when Greek archaeologist Dora Katsonopoulou launched the Helike Project to locate the site of the lost city. In 1994 a magnetometer survey was carried out in collaboration with the University of Patras in the delta region near the Corinthian Gulf where Helike was suspected to be located, revealing the outlines of a buried building. 

Excavations followed, unearthing a large Roman building with standing . But the Classical remains of the city of Helike itself were rediscovered in 2001, buried under vestiges of an ancient lagoon. Since then, excavations have been conducted in the Helike delta area every summer. These excavations have uncovered significant archeological finds dating from the time of Helike’s founding to the time of its revival during Hellenistic and Roman times.