Archaeological site Pavloρetri in Laconia Regional Unit

You're standing on the coast at Pounta, in the far south of the Peloponnese, looking out over Vatika Bay. See that little islet just offshore? That's Pavlopetri, which means Paul's stone. And between that islet and the beach, only three to four metres down, lies an entire town. At around five thousand years old, it's the oldest submerged city known anywhere in the world.