5 Ancient Cities That Are Now Underwater

For more than 2,000 years, a legendary Egyptian city lay buried beneath both sand and sea at the mouth of the Nile River. The Greeks named the city Heracleion, after the mythical hero Herakles, and the Egyptians called it Thonis. During the Ptolemaic Dynasty, Thonis-Heracleion was the port of entry for all Greek ships traveling to Egypt and home to the magnificent temple of Amun, where the Ptolemaic pharaohs received their divine authority.

The historian Herodotus (5th-century B.C.) wrote about the grandeur of Thonis-Heracleion, and its ancient location was referenced by geographer Strabo (1st century B.C.), but the once-magnificent city and its temples seemed to disappear without a trace.

Then, in the 1990s, a team of underwater archaeologists led by Franck Goddio solved a mystery that had eluded fellow archaeologists for millennia. Armed with high-tech scanners and sonar, Goddio’s team detected an anomaly more than four miles off the Egyptian coast that covered nearly a square mile of the seafloor.

“When we dove there for the first time, we saw only sand, because there was nothing to see,” says Goddio. “Everything was buried under the sediment.”

As soon as Goddio began to excavate, though, his team hit the archeological equivalent of the lottery. Among the astounding finds hidden in the murky Mediterranean waters were two colossal red-granite statues of a Ptolemaic king and queen, each measuring 15 feet tall and weighing several tons. Goddio’s most-prized find was a fully intact, black-granodiorite stele covered in hieroglyphics. The six-foot object bears a royal decree from Pharaoh Nectanebo I that dates to 380 B.C.

Over more than two decades of continuous excavation, the site at Thonis-Heracleion has revealed two temples, the largest Egyptian statue of a god (Hapy), countless bronze ritual objects and more than 100 shipwrecks, some dating to the violent destruction of the city itself.

Built on clay soils at the mouth of the Nile, Thonis-Heracleion was uniquely vulnerable to earthquakes. Around 150 B.C., the city was struck by a massive earthquake followed by a tsunami. During the shaking, the foundations of the city were toppled by soil liquefaction. A powerful wave then washed it all into the sea.

“In a fraction of time, the city and all of its monuments went down seven meters (~23 feet) and the sea covered everything,” says Goddio, who estimates that only 5 percent of the buried city has been excavated.

At the height of its wealth and decadence, Port Royal, Jamaica was known as “the wickedest city on earth.” During the 17th-century, the British outpost was the busiest port in the Caribbean, and a notorious tropical playground where moneyed merchants rubbed shoulders with pirates and prostitutes.

Then, at precisely 11:43 AM on June 7, 1692, Port Royal was struck by a massive earthquake and tsunami that buried two-thirds of the once-glittering city under the sea.

An Anglican minister who survived the disaster reported: “[W]e heard the Church and Tower fall, upon which we ran to save ourselves; I...made towards Morgan's Fort, because being a wide open place I thought to be there securest from the falling houses; but as I made towards it, I saw the earth open and swallow a multitude of people; and the sea mounting in upon us over the fortification.”

Before its destruction, Port Royal was home to an estimated 7,000 residents, including 2,500 enslaved people. The wealthiest citizens lived in stately brick homes and entertained themselves at billiard halls, saloons and brothels. The British captured Port Royal from Spain in 1655 and over the next 40 years it became one of the most important trading posts in the New World.

Port Royal’s wealth came from the slave trade, as well as sugar and other raw materials. “Privateering” was also big business in the Caribbean. The British Crown contracted with privateers or “buccaneers” to raid French, Spanish and Dutch merchant vessels and split the spoils.

According to the Anglican minister, the destruction of Port Royal was divine punishment for “a most Ungodly Debauched People.” More than 2,000 people died during the initial earthquake and tidal wave, and an estimated 3,000 more died later from injury and disease.

Underwater archaeological excavations of Port Royal began in the 1950s. That’s when Edwin and Marion Link found a centuries-old pocket watch that had stopped at exactly 11:43 a.m. The underwater ruins are remarkably well-preserved and have provided archeologists with a detailed picture of daily life in the 17th century. In 2025, Port Royal was named a UNESCO World Heritage Site.

Discovered in 1984 in the shallow coastal waters near Haifa, Israel, Atlit-Yam is a Neolithic site that was first settled around 6900 B.C., making it by far the oldest known human settlement found underwater.

The inhabitants of Atlit-Yam were farmers and fisherman who occupied a fertile stretch of land left behind by the receding Mediterranean Sea. They planted wheat and pastured animals. They also dug deep wells lined with stone to reach freshwater aquifers more than 30 feet underground.

The earliest settlers of Atlit-Yam came during the Pre-Pottery Neolithic period, characterized by the advent of rectangular dwellings and an increased reliance on domesticated animals. Archeologists have recovered thousands of flint artifacts at Atlit-Yam, including sickle blades, arrowheads and knives.

One of the most intriguing discoveries at Atlit-Yam was a circle of large, upright stones that some archeologists compare to Stonehenge. The stones surround a natural spring and may have served a ceremonial purpose—as an open-air sanctuary where the ancient farmers made offerings for their agricultural bounty.

Atlit-Yam was abandoned roughly 600 years after it was first settled. The encroaching Mediterranean Sea eventually swallowed the village, burying it under 30 feet of water.

In the clear, coastal waters off the Peloponnese region of southern Greece lie the remains of what some archaeologists believe is the oldest submerged city in the world. The Bronze Age site, called Pavlopetri, was occupied between 2800 and 1200 B.C., centuries before the Classical Greek period. Primitive settlements like Atlit-Yam may date to an earlier period, but Pavlopetri appears to be the oldest planned city found underwater.

First discovered in the 1960s, Pavlopetri has only recently been fully excavated, revealing a well-preserved network of stone-paved streets, rock-cut tombs and ceremonial buildings. Archeologists believe that one large, rectangular structure may have been a megaron—a Mycenaean great hall that was a precursor to Greek temples.

It’s unclear exactly why Pavlopetri sank underwater around 1,000 B.C., but it was likely a combination of earthquakes and sea-level changes in the Mediterranean. Today, the site is between 10 to 15 feet underwater. Since no other settlements were built on top of it, the ruins of Pavlopetri offer clues to daily life in a Bronze Age Mediterranean village. Archeologists have recovered thousands of pieces of ancient pottery from the submerged site, including large, intact Minoan jars and amphorae that point to a once-lively sea trade.

The World Monuments Fund identified Pavlopetri as under “serious threat” from large ships that pass through Vatika Bay in the Peloponnese, and also from looters stealing artifacts from the site.

Dubbed the “Las Vegas of the Roman Empire,” the thermal baths of ancient Baiae were an anything-goes playground for Roman elites in the 2nd century B.C. Today, the sunken resort town off the coast of Naples is one of the few submerged ancient archaeological sites open to public tours.

Baiae is not far from Mount Vesuvius, and the entire region is known as the Phlegraean Fields, a highly active hydrothermal zone within a collapsed volcanic caldera. Ancient Romans flocked to Baiae for its relaxing thermal baths and constructed lavish villas to host hedonistic parties and conceal illicit love affairs.

Unlike the “sinful” city of Port Royal, Baiae wasn’t struck down by a devastating earthquake, but was slowly swallowed up by the sea through a geological process called bradyseism, in which the land above a hydrothermal zone periodically rises or subsides. Two thousand years ago, the ornately decorated villas and baths of Baia were at sea level, but now they’re 20 to 30 feet beneath the Gulf of Pozzuoli.

Today, visitors can snorkel or scuba dive through the sunken ruins at the Underwater Archaeological Park of Baiae (glass-bottomed boats are also available). The underwater attractions include beautifully tiled marble floors, “pleasure grottos” and sunken statues.