Nearly 44 years ago, the villagers of Kallio in central Greece watched as their homes disappeared under the waters of Lake Mornos. The artificial reservoir was created after the construction of the Mornos Dam to supply Athens with drinking water. Families were forced to leave behind centuries of life, rebuilding their community elsewhere.
This autumn, drought has pulled the lake’s waterline back to its lowest point since 2014, revealing Kallio’s stone ruins once again. Satellite data confirmed the lake’s surface has shrunk dramatically, exposing remnants of streets and houses long thought lost.
Kallio is a modern story of displacement—but most of Greece’s underwater ruins date back thousands of years, reminders of how tectonic shifts, coastal erosion, and rising seas reshaped civilizations.
Here are eight of Greece’s most remarkable submerged cities, each offering a glimpse of history you can still swim above today.
The Sunken City of Epidaurus
Just a few hours from Athens, near the Bay of Agios Vlasios in Ancient Epidaurus, lies one of Greece’s most accessible underwater cities. At a depth of barely two meters, swimmers can clearly see:
- Foundations of monumental buildings
- Mycenaean tombs from the 12th century BC
- Ancient amphorae and even paved streets
Archaeologists believe the site was once a commercial hub and later home to a large Roman villa (Villa Rustica) belonging to a wealthy landowner.
Local cultural agencies have launched conservation projects to protect the ruins from erosion and looting. Today, curious swimmers with just a mask and snorkel can glide over an ancient city without scuba gear.
Pavlopetri, Laconia: The Oldest Sunken City
Off the coast of Viglaphia, Laconia, facing Elafonisos island, lies Pavlopetri, often called the oldest known submerged city in the world. Discovered in the 1960s and digitally mapped in 2009, it preserves a detailed Bronze Age urban plan: streets, courtyards, multi-room houses, and even water management systems.
Dating back to the Early and Middle Bronze Age, Pavlopetri thrived into the Mycenaean era. Evidence suggests its inhabitants worked in textiles and traded widely, including with Crete.
Today, visitors can swim with a snorkel above this extraordinary underwater time capsule.
Methoni, Messenia: Earthquake and Ruins
In the 1980s, divers identified a Bronze Age settlement beneath the waters of Methoni Bay in Messenia, at depths between 3.5 and 5.5 meters. Archaeologists believe an earthquake sent the city beneath the waves.
Excavations uncovered preserved walls, Byzantine-to-Ottoman-era shipwrecks, a medieval aqueduct, and even the breakwater of an ancient port. Among the most striking finds: a burial of two infants in jars (enchytrismoi), as well as references to temples dedicated to Athena Anemotis and Artemis. A nearby well, mixed with pitch, has even been interpreted as the first recorded oil extraction in Greek lands.
Plytra, Laconia: A City Shaken Into the Sea
Between the bays of Skoteinos and Arasma, the ruins of Plytra lie scattered on the seabed. Tectonic shifts submerged much of its urban fabric. Divers can spot:
- Rectangular stone blocks
- A well with hydraulic cement
- Remnants of harbor works and towers
- Mosaic floors that reappear when the sand shifts
These mosaics tell of prosperity during the Hellenistic and Roman periods.
Salanti, Argolis: A Bronze Age Settlement
Near the Didyma Bay, just north of the famous Franchthi Cave, archaeologists uncovered an extensive settlement covering dozens of acres. Stone walls, some double-layered, point to a Early Bronze Age community. Rising waters and alluvial deposits eventually swallowed it.
Puntazéza, Lavrio: Sacred Shores
In the ancient “Salaminian Strait,” mentioned in classical inscriptions, lies a mix of rural estates, sanctuaries, wells, and homes. Today, parts of its shoreline are underwater, where the foundations of public buildings remain visible. Geological shifts and rising seas gradually pulled this ancient activity below the surface.
Anthedon, Euboea & Northern Aegean Harbors
The submerged port works of Anthedon include quays, breakwaters, and stone structures dating from the Archaic to Hellenistic periods. Similar engineering marvels appear at Abdera, with semicircular sea towers and successive harbor phases. These testify to the advanced maritime engineering of ancient Greek builders.
Helike, Achaea: Atlantis of Greece
Finally, there is Helike, the legendary city of Poseidon, destroyed by an earthquake in the 4th century BC. Ancient texts describe it sinking beneath the sea, inspiring myths of Atlantis. Modern excavations reveal that its destruction was more complex—linked to inland waters, not just the open sea. Recent digs unearthed structures buried under sediment, confirming Helike’s tragic fate.
A Living Memory Beneath the Waves
From Epidaurus to Laconia, these submerged cities remind us how fragile civilizations are in the face of nature. Yet they also offer something rare: a chance to swim, quite literally, through history.
Whether it’s the Bronze Age streets of Pavlopetri, the Roman villa of Epidaurus, or the legendary ruins of Helike, Greece’s underwater cities invite us to explore a world where time stands still, waiting just beneath the surface.
