The find was made on the Peloponnese Peninsula, south of Athens, in an area close to Kiladha Bay, which is known to be of historical importance. It is protected by the Greek government, who strictly regulates diving to prevent the looting of archaeological artefacts. But, a group of researchers from the University of Geneva made a stunning discovery while training at the nearby Lambayanna Beach. Divers first spotted fragments of pottery below the surface, hinting at the possibility of a submerged settlement, and returned a year later to conduct a full investigation. Overseen by the Swiss School of Archaeology in Greece, in collaboration with the Greek Ministry of Culture, they used the world’s largest solar-powered boat – the PlanetSolar – to aid in their search.

What baffled the archaeologists though, was the settlement contained at least three horseshoe-shaped foundations attached to the wall line, believed to be a type of defense fortification unseen anywhere else in Greece. Julien Beck, an antiquities professor at the University of Geneva, said: 

“The importance of our discovery is partly due to the large size. The chances of finding such walls underwater are extremely low. The full size of the facility is not yet known. We do not know why it is surrounded by fortifications.”

The team found more than 6,000 artefacts connected with the settlement, including paved surfaces that appear to be streets, as well as a wide array of pottery and stone tools.

The submerged structures found by the researchers date to around the same period as the pyramids of Giza and early Minoan Settlements in Crete. But they predate the first great Greek civilisation, the Mycenaean, by roughly 1,000 years.

Though the experts are still determining the extent of their discovery, Prof Beck compared its importance to the town of Lerna, located in the nearby Gulf of Nafplion. Believed to be the site of Hercules’ battle with the many-headed Hydra in Greek mythology, Lerna has long been used as a reference point for researchers because of the ceramics and architectural structures found there.

Prof Beck and his colleagues did not make a guess as to why the city sank below the ocean’s surface thousands of years ago, though rising sea levels and shifting tectonic plates have been suggested as possibilities.

The research team hopes the artefacts will enable them to “learn more about trade, shipping, and day-to-day life from the period” in the future. They believe further investigations around Lambayanna Beach will provide new insight into a dense network of coastal settlements spread throughout the Aegean Sea.