Scientists do extraordinary things every day but sometimes, the sheer exceptionality of their endeavours just takes your breath away. This is exactly what happened when I saw pictures of divers unearthing secrets of a great Egyptian city from the depths of the Mediterranean Sea.

Named Thonis by the Egyptians who built it but known as Heracleion to the Greeks of the time, this great city was once a central part of ancient Egypt. Older than Alexandria, Thonis was probably founded during the eighth century BC. The city began on a downstream shore of the great Nile river where the land was fertile and freshwater was abundant. Thonis was strategically situated between the Mediterranean Sea and a great mostly landlocked lake, which also linked to the Nile river. The lake could (and indeed would) essentially be used as a huge parking space for ships.

All in all, Thonis was at a perfect location for a marine port. And a great port it became. Thonis bridged the entire world to Egypt, especially the important Greek world but also that of the Phoenicians.

But constructing a huge city on the bank of a river and the shore of a sea comes with a risk. Thonis took that risk but ultimately paid for it with its life. One and a half centuries after its beginnings, the great city of Thonis sank into the depths of the very sea that had allowed it to prosper for so long. Although scientists are still unsure about the exact cause of this cataclysm, most believe that a rise in sea level coupled with a sudden collapse of unstable sediment-heavy earth caused the city to carve in and plunge into the abyss.

It took more than 1200 years for the city to be rediscovered. In the intervening period, many became convinced that Thonis was nothing but a myth despite the fact that historical reports of the city were not lacking. It was believed that Helen of Troy (the face that launched a thousand ships!) herself, accompanied by her lover Paris, visited the city. Some stipulated, albeit backed with less scientific rigour, that even Hercules set foot on Thonis. With no concrete physical proof of the city though, it was only natural that doubts about its existence would creep in.

But in 2000, a team of scientists famously rediscovered the sunken city after a four-year geophysical survey. Led by renown French underwater archaeologist Dr. Franck Goddio, an Institut Européen d'Archéologie Sous-Marine (IEASM) team located the remains of Thonis beneath the waters and mud of Aboukir Bay, about 32 km northeast of Alexandria. Thonis was there, reposing silently in the abyss but no less majestically as is often the case with past sunken grandness.

It is only now however, 13 years after its rediscovery, that the team is beginning to comprehend the real grandness that was Thonis. The images and videos of the excavation that the team is releasing paint a portrait of a city frozen in time.

Thonis was a city of buildings: to the south resided a huge temple, devoted to the then-supreme god Amun-Gereb; the north and east of the city were predominantly devoted to the port; the west was bordered by the lake, steaming with ships that would either halt at Thonis for a while or make their way across the narrow channel that linked it to the Nile river.

But Thonis was also a city of opulence. The team has unearthed gold coins, bronze coins, gigantic five-metre sculptures, sarcophagi and hundreds of smaller statues of other gods from the sea floor. Considering that Thonis was a major port of the region at the time, these findings are not surprising. Equally unsurprising are the remains of the more than 64 ships the team uncovered lining the sea floor of the region.

Rediscovering a great sunken city is amazing not just in terms of the actual discovery but also in terms of the scale of the scientific endeavour. As mentioned, it took the team four years to actually rediscover Thonis and another thirteen years for it to get an adequate view of what it looked like centuries ago.

For such precious archeological findings as the remains of Thonis, conservation of the unearthed objects starts as soon as they reach the boat itself. The objects are first cleaned, identified and inventoried. Rapidly, the boat crew rather grotesquely removes as much salt as possible from the objects by regularly soaking them in buckets of fresh water. Salt removal is primordial since salt can corrode certain metals or magnify fissures and cracks as it crystallises. Depending on the initial condition of the repatriated objects, the crew may choose to perform a further more ardent round of salt removal, making use of adequate chemicals, on the boat itself.

Once taken ashore, the objects are sent to the super-sophisticated Alexandria Conservation Laboratory for Submerged Antiquities. There, specialists continue the conservation and restoration works. Using mechanical, chemical and electrochemical procedures, the objects are adequately treated depending, among other thing, on the material they are made of. Metallic objects for instance may go through further rounds of salt removal before being cleaned with ultrasonic scalpels, fibreglass brushes and other fancy apparatus I didn't even know existed. Ceramic objects on the other hand go to storage areas, meticulously kept at a perfect temperature and humidity combination.

The amount of work (and money surely) spent on this endeavour is formidable. But as you look at the pictures today, possibly stare at the objects unearthed one day in a museum and listen as the story of the great city of Thonis gets puzzled together, you have to admit that the work was totally worth it.

Indeed, rediscovering the grandness of a past city is one of those few things that can take your breath away.

Image credits: Top map: franckgoddio.org (imagery from Google); Bottom: World Imaging (from Wikimedia Commons).

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