Drowned cities: Myths and secrets of the deep

Deep Secrets

The idea that great cities, rich in forgotten knowledge and treasure, lie hidden beneath the sea holds immense appeal. Scarcely a year goes by without someone claiming to have found Atlantis. But what’s really out there under the waves?

Jo Marchant looks at some of the sunken towns and cities discovered worldwide, and separates the facts from the myths.

Built on Sand: Herakleion and Eastern Canopus, Egypt

On Egypt’s northern coast, where the Nile delta meets the sea, there once stood two cities of such wealth and grandeur that they were famous throughout the ancient world. Today, their remains lie buried beneath a shallow bay.

Around 500 BC, the ports of Herakleion and Eastern Canopus were thriving trade centres, the gateways into Egypt for Greek ships passing down the Nile. These cities were also important religious centres, their temples attracting thousands of pilgrims each year. Yet until recently, almost all that was known about them came from ancient texts. The Greek historian Herodotus wrote in the 5th century BC that they looked like the islands of the Aegean, but set amid a marsh.

Inspired by such accounts, French businessman and archaeologist Franck Goddio began surveying an area a few kilometres west of the Nile delta called Abu Qir Bay. Goddio has been running underwater excavations at nearby Alexandria since the early 1990s. But Abu Qir may yield even more exciting results.

In 2000, Goddio revealed the discovery of two sets of ruins, including walls, temple remains, columns and statues, buried in sand under 7 metres of murky water. The first set of ruins lies 1.6 kilometres from today’s coastline. In annual excavations there since 2000, Goddio’s team has retrieved coins, amulets and jewellery from as far back as the 6th century BC. A slab of black granite (pictured above), inscribed with a tax edict, names the city as Heracleion and it is signed by Pharaoh Nectanebo I, who ruled from 380 to 362 BC.

The team has also identified two temples, dedicated to the Greek hero Heracles and the god Amon (the Greek version of the Egyptian deity Amun). Just to the north of the Heracles temple, the divers discovered many bronze objects, which were probably dropped into an ancient waterway as offerings. “We have found ritual deposits made by the priests in quite precise places that were known only to them,” says Goddio. “We feel as if we are penetrating to the heart of the ancient liturgy.”

A few kilometres away, the second set of ruins has been identified as Eastern Canopus. There, divers have discovered ceramics, parts of temple doors, coins with the profile of Cleopatra, who ruled Egypt in the 1st century BC, and a black granite shrine from the 4th century BC, dedicated by Nectanebo I, which boasts a series of astronomical and calendrical inscriptions.

The two cities were connected by a network of channels and waterways to a now-defunct branch of the Nile, geophysicist Jean Daniel Stanley of the Smithsonian Institute in Washington DC reported in 2006 (Geoarchaeology, vol 21, p 504). The cities’ grand stone buildings were perched at the river’s edge, built on mud and sand without any solid foundations or pilings. When the Nile suffered particularly high floods, the extra weight of the water would have caused the ground beneath them to collapse, says Stanley.

The damage may not have been too disastrous at first. Huge cracks beneath some of the buildings at Eastern Canopus were deliberately filled with sand, and artefacts and coins found at the site date from as late as 740 AD. However, fallen columns and statues, as well as human skeletons and valuables found underneath toppled walls, suggest the end came quickly. After centuries of fighting the subsidence, a particularly dramatic flood, known from historical records to have occurred in 741 or 742 AD, finished the city off, Stanley thinks. During the same flood this branch of the Nile may have shifted eastwards (Nature, vol 412, p 293).

“Human skeletons and valuables found underneath toppled walls suggest the end came quickly”

For the cities’ inhabitants, the economic advantages of building on such a precarious site probably eclipsed long-term safety considerations – a warning, says Stanley, to coastal cities of today.

Pitate HQ: Port Royal, Jamaica

Notorious as a hotbed of piracy and prostitution, the 17th-century Caribbean town of Port Royal was known as “the wickedest city on Earth”. Then, one day, it was swallowed up by the sea.

Port Royal, located at the mouth of Kingston Harbour, Jamaica, was once the biggest English colony in the New World, with a population of around 10,000. Much of its wealth came from pirates and privateers who attacked treasure ships heading back to Europe from the Spanish Main. The city’s downfall came not from its loose morals but the fact that it was built on a sand spit (pictured right), less than a metre above the water table. When an earthquake struck the area just before noon on 7 June 1692, the tremors caused the sand to liquefy.

“Buildings that were once on a solid foundation are now sitting on a liquid,” says Donny Hamilton, an archaeologist at Texas A&M University in College Station. “A building can drop 15 feet straight down without any of the bricks in the floor being displaced.” Two-thirds of the city sank into the harbour, killing 2000 people that day.

Hamilton led a series of excavations at the site between 1981 and 1990. Eel grass now coats the harbour floor, overlaying a thick layer of dead coral deposited by a hurricane in 1744. This covered the buildings, preserving many of them intact – multi-storey brick houses and shops interspersed with shabbier earth constructions, which once lined bustling streets of sand.

Their contents reveal life as it was the moment the disaster hit. In one home, “we found stacks of pewter plates, iron skillets, charcoal in the hearth, knives, spoons and forks”, says Hamilton. “And we found three children under the walls.” Perhaps the most dramatic find at Port Royal, though, dates from an expedition in the 1960s: a pocket watch, its hands frozen at precisely 11:43 am.

Traces of a revolution: Atlit-Yam, Israel

One kilometre out in the Mediterranean Sea, near Haifa, Israel, an ancient village lies hidden beneath the waves. It has been so well preserved by the sandy seabed that weevils sit in the grain stores, human skeletons lie undisturbed in their graves, and a mysterious stone circle still stands as it was first erected.

This is Atlit-Yam. The 40,000-square-metre site dates from around 7000 BC, making it one of the earliest – and largest – drowned settlements known. There were no organised streets, so the site is described as a village rather than a city, but its people lived in spacious stone houses, complete with paved floors, courtyards, fireplaces, storage facilities and wells.

The site lay buried for 9000 years until quarrying of sand exposed some of the ancient remains. They were spotted in 1984 by Ehud Galili, a marine archaeologist and member of the Israel Prehistoric Society, when he was surveying the area for shipwrecks. Their exposure, however, has put many of the artefacts in grave danger.

Since 1984, Galili has dived at the site every winter. He waits for storms to shift the sands, then hurries to chart newly visible areas and remove any objects that could be damaged by the sea. “We only excavate where there is imminent danger of destruction,” he says.

The site provides unprecedented insight into life in Neolithic times – when people had just discovered how to domesticate plants and animals. “It was the biggest revolution in the history of mankind,” says Galili. Animal bones show that the inhabitants of Atlit-Yam hunted wild animals, but also kept sheep, goats, pigs, dogs and cattle. They grew domesticated wheat, barley, lentil and flax, but were also master fishermen – bones reveal piles of fish ready for trade or storage. Bone fishhooks were used, but the men also dived for seafood – four male skeletons have ear damage caused by diving in cold water. Last year, the skeletons of a woman and child even revealed the earliest known cases of tuberculosis (PloS ONE, vol 3, p e3426). Human graves were scattered among the houses rather than being in a separate graveyard, and the village had several stone-paved water wells. But most intriguing is a stone semicircle made up of seven 600-kilogram megaliths. “Like Stonehenge but smaller,” says Galili. It had a freshwater spring in the middle and cup marks are carved into the slabs, so the monument may have been used for some water ritual.

“Most intriguing is a stonecircle made of seven megaliths, with a natural spring in the middle and cup marks on the slabs”

At the time, sea levels were still creeping upwards after the last ice age. Galili believes Atlit-Yam’s wells gradually became contaminated with saltwater – he found one was used as a rubbish tip in later times. This would have forced people to abandon their homes, and the village was engulfed by sand dunes and then submerged.

Built by Nature: Yonaguni, Japan

The tiny Japanese island of Yonaguni, near Taiwan, has become famous for the huge submerged rock structures found near its shores – the ancient city of a lost civilisation, some claim.

Imposing sets of steps and terraces rise up through the clear water from around 25 metres depth. The structures, with their flat surfaces and near right angles, certainly look deliberately carved (pictured left). Masaaki Kimura, a geologist at the University of the Ryukyus in Okinawa, claims he has identified a huge pyramid, along with castles, monuments and a big stadium, all connected by roads. He says he has also found walls and water channels, as well as quarry marks, stone tools and a stone tablet carved with ancient lettering.

Though popular, Kimura’s claims about Yonaguni are disputed. Robert Schoch, a geologist at the University of Boston who has dived at Yonaguni many times, thinks the formations are mostly natural. They are made of bedrock, rather than built with separate blocks, and Schoch points out that the rock is sedimentary, with horizontal layers that break along parallel lines as they erode. The region’s tectonic activity also splits the rock along vertical fault lines. So the strong currents that sweep the area would erode rock along these lines, carving out platforms and steps, he says. “You get a regular blocky structure quite naturally.”

Kimura’s walls could be horizontal platforms that fell into a vertical position when the rock beneath them eroded. And Schoch says the “roads” are just channels swept clean of debris by the currents.

What’s more, Kimura initially thought the structures were created more than 6000 years ago, when the area would have been above sea level. But his own recent dating work, reported at the 21st Pacific Science Congress in 2007, show they could only have been “constructed” between 3000 and 2000 years before present, when sea level was close to 20th century levels.

Kimura speculates that tectonic activity caused the land to sink tens of metres after this time, but it would be very surprising if this was the case, says Richard Pearson, a specialist in the archaeology of east Asia who spent most of his career at the University of British Columbia, Vancouver, Canada.

On Yonaguni Island, archaeologists have unearthed the remains of small camps behind the sand dunes, including large fireplaces, stone tools and thick brown pottery, dating to 2000 to 2500 BC. But the communities on the island were small. “They are not likely to have had extra energy for building stone monuments,” says Pearson.

And while people in nearby Taiwan at this time were building with stone, there’s no evidence for anything like the stepped monoliths at Yonaguni. However, the rock formations, which are visible without specialised diving equipment even today, may still have been important to the locals. It is possible that they “touched up” parts of the rock close to the shoreline, says Schoch, making them appear artificial.

Story City: Atlantis

Everyone has heard of the lost city of Atlantis. The myth began with the Greek philosopher Plato. In 360 BC, he wrote a book whose characters describe Atlantis as an island bigger than “Libya” and “Asia” together, which existed 9000 years earlier “in front of the Pillars of Hercules” that flank the entrance to the Mediterranean Sea.

The Atlanteans were a great naval power but became greedy and morally bankrupt, according to Plato’s story. After they led a failed attack on Athens, a natural disaster sank the island in a day and a night, and the spot became a mud shoal, making it impassable and unsearchable. There are many theories for locations that might have inspired Plato. For instance, German physicist Rainer Kuhne thinks it was a region of the southern Spanish coast, destroyed in a flood between 800 and 500 BC. Satellite photos show two rectangular structures in the mud, which Kuhne thinks could be the remains of temples described by Plato.

Swedish geographer Ulf Erlingsson says only Ireland matches Plato’s description. Others think Atlantis is Spartel Island, a mud shoal in the Strait of Gibraltar that sank into the sea 11,500 years ago.

Classical scholars, however, point out that few took Plato’s account literally before modern times. “The idea was that we should use the story to examine our ideas of government and power. We have missed the point if instead of thinking about these issues we go off exploring the seabed,” philosopher Julia Annas writes in Plato: A Very Short Introduction.

Homeric Home Port: Pavlopetri, Greece

When fleets of ships carrying warriors from all over Greece set off to do battle with the great fortress city of Troy, perhaps some of them sailed from Pavlopetri, the oldest known submerged town. “It was perfectly situated to have been a major stopover,” says Nicholas Flemming, a marine geologist at the University of Southampton, UK, who discovered the settlement when diving in the area in 1967.

Once a busy Bronze Age port, Pavlopetri now sits under 4 metres of water, in a sandy bay in Laconia, near Greece’s southern tip. Flemming surveyed the site in 1968, with the help of measuring tapes and a group of students. He discovered an organised grid of streets and courtyards lined with houses of uncut stone, as well as scattered graves and broken pottery that dated from the Mycenaean period, from 1600 to 1100 BC.

There are no signs of docks or harbour structures at Pavlopetri. Instead, researchers think trading vessels, 10 to 20 metres long, would have been anchored in the shallow water of the bay and their cargo unloaded onto horses or perhaps wooden jetties, while warships were dragged up onto the beach.

For 30 years no further work was done at Pavlopetri. But in summer 2009, archaeologist Jon Henderson from the University of Nottingham, UK, working with Elias Spondylis of the Greek government’s Ephorate of Underwater Antiquities, carried out a detailed digital survey using laser-based positioning and state-of-the-art sonar scanning. They found that the site is much larger than first thought – since 1968, shifting sands have exposed a further 150 square metres of remains. They also uncovered two rock cut tombs, a large ceremonial hall and pottery dating back to at least 2800 BC.

“All this begins to make Pavlopetri much more important than previously thought,” says Henderson. “It was maybe one of the main sites in Laconia, with important royals living there.” That raises the possibility that the town might have played its part in the adventures immortalised by Homer. “It’s quite possible that the people who left for Troy from Laconia, left from this port,” says Henderson. “I would love to think it was an important port in Homer’s time,” agrees Flemming.

“It is quite possible that the people who left to go to Troy, as described in Homer’s Iliad, left from this port”

Meanwhile, Flemming is studying the coastline to work out exactly how Pavlopetri ended up underwater. The most likely explanation is tectonic activity. The town was abandoned around 1100 BC, but whether it was finished off by several small quakes or one catastrophic event is still an open question.

Drowned Cities: Dunwich, UK

The water was so black that Stuart Bacon couldn’t see the watch on his wrist no matter how bright his diver’s lamp. Then the sediment cleared just enough for him to catch a glimpse of a stone church tower, crawling with hermit crabs, lying on the sea bed.

In medieval times, Dunwich was a busy fishing port, capital of East Anglia and one of the 10 largest cities in England. But it was doomed from the start. The city was built on soft sedimentary rock, easily eroded by the region’s fierce waves.

The first big blow came in 1286, when a giant sea surge claimed four hundred houses and shops. Since then, Dunwich has slowly crumbled into the sea. Most of the debris washed away, but the ruins of its stone churches remain in their original locations on the sea bed, forming an eerie ghost map of the old town that is submerged in ever deeper water as the coastline recedes.

One by one the city’s 16 or so churches have disappeared over the cliffs, until the last, All Saints, met its end in 1919. Thanks to the difficult diving conditions, there was no serious attempt to investigate what remained underwater for more than 50 years, until Dunwich enthusiast Bacon located All Saints’ church tower in 1971. Since then, he has dived at the site hundreds of times, leading groups of local divers armed with metal rods to probe the darkness.

Last year, Bacon teamed up with geographer David Sear of the University of Southampton, UK, to survey the seabed using sonar. They located the ruins of St Nicholas and St Peter’s churches, which collapsed over the cliffs in the 15th and 17th centuries respectively. The rest of the site, however, was buried in several metres of sediment.

In June, local divers retrieved flint and mortar from St Peter’s church and filmed its carved stonework in a rare moment of visibility. And in July, a team from Wessex Archaeology used a sonar method called sub-bottom profiling to locate one more church within the mud.

More sub-bottom profiling is planned for next year. By looking further from the coast, Sear hopes to find older churches, which should be in better condition. “There’s evidence that the cliff got lower as you went seaward, so maybe the older part of town went over a much smaller cliff, or didn’t go over a cliff at all.” The harbour area, to the northeast of town, was also low-lying so would have been submerged without a cliff drop.

Meanwhile the disappearance of Dunwich – now reduced to a village – continues. Of the medieval churches, a single tombstone of All Saints churchyard is all that remains.

Source: Published by Jo Marchant for New Scientist.