The Imperial Roman Harbour Buried Under Constantinople | Emperor's Lost Harbour | Timeline

One of the great privileges of working at History Hit and making films together with our team at Timeline is the access we get to extraordinary historical locations like this one, Stonehenge. I'm right in the middle of the stone circle now. It is an absolutely extraordinary place to visit. If you want to watch the documentary like the one we're producing here, go to History Hit TV. It's like Netflix for history and if you use the code TIMELINE when you check out you'll get a special introductory offer. See you there. Constantinople, the former capital of the great Roman and Byzantine empires, is now the Turkish city Istanbul, straddling both European and Asian shores of the Bosphorus Sea for more than 3,000 years. Yet despite its remarkable history, most of the city's past is shrouded in mystery. But in 2004, Turkish engineers began digging an immense tunnel underneath the Bosphorus to connect Europe and Asia by train. And it was here that they stumbled across something extraordinary, one of the richest archaeological sites ever unearthed. But with pressure to complete Istanbul's modern rail system mounting, will scientists be able to uncover the mysteries of Constantinople's past before their unique window on history closes forever? 17 million people live in Istanbul, on both sides of the Bosphorus, with at least 1 million commuters crossing it day by day. Only two bridges and a number of ferries transport the crowds and it's hardly enough. That's why in 2004, the Turkish government embarked on an ambitious plan to build a brand new public transit system that would involve digging the world's deepest tunnel under the Bosphorus, finally connecting Europe and Asia by train. Hussein Belkaya is in charge of constructing this transportation megaproject known as Marmaray, named for the Turkish word for rail. Now we are traveling on the alignment of Marmaray project now. The world's deepest immersed tunnel is just laying under us. The tunnel had to be placed more than 50 meters under the surface, making it the deepest immersed tunnel in the world. 11 concrete elements, each of them 135 meters long and weighing 18,000 tons, were immersed by customized boats to accomplish the task. Despite heavy waves and strong currents, the concrete elements assembled for the construction of the tunnel had only two or three centimeters tolerance of margin. When completed, the system will be 76 kilometers long and carry 75,000 passengers per hour in both directions. Tunneling beneath the city are enormous TBMs, or tunnel boring machines, the size of a jumbo jet and shaped like the tunnels they create. They're so large you can't film the exterior, only what's happening inside. We are here in the end of our tunnel boring machine. This is a 135 meter long factory. It drills the hole, locates the segment, does the injection ground and leaves a completed tunnel behind. The Marmaray transit system was supposed to open its doors in April 2010, but from the very beginning, the project of the future has been frustrated by history. Almost everywhere engineers dug, they stumbled across priceless artifacts from over 3,000 years of Istanbul's past, slowing construction of the tunnel down to a crawl. And here in the Istanbul neighborhood of Yenikapi on the site of the future subway station is one of the largest discoveries so far, one that is transforming our knowledge of Istanbul's hidden history. It spreads over an area the size of 10 football fields and dates back to precisely the period of history from the 4th to the 15th centuries when Istanbul was called Constantinople and when the Byzantine Empire ruled the world. Zeynep Kiziltan, the director of the Archaeological Museum of Istanbul, leads the large scientific crew charged with processing the enormous amount of artifacts uncovered here every day. So far, the site has yielded up an amazing array of Constantine relics, including 30,000 animal bones and hundreds of human skeletons. But what really makes this archaeological find so unique had nothing to do with urban artifacts but with the sea. The first clue was these wooden poles, an entire row of supports for an ancient jetty or pier. And then a boat. And another. And another. A total of 37 ancient Byzantine shipwrecks dating from the 6th to the 11th century, almost all astonishingly well preserved. It was beyond anyone's imagination. They had stumbled across Constantinople's historic harbor, lost from view for over 800 years. 70 meters beneath the surface, subway engineers tunnel their way closer and closer to the ancient port and its treasures. So far, the archaeological dig has cost the transit system over 30 million dollars and mounting. Construction of the station has already broken ground, and archaeologists must work shoulder to shoulder with the engineers, with the ever-present threat of bulldozers just meters away. However, there are some limits and basic principles in archaeology. We cannot remove anything from the site without sufficient documentation and examination in place. Ufuk Kokabas is a nautical archaeologist with the University of Istanbul, and the man responsible for making sure not one splinter of these boats gets left behind. This is the largest shipwreck collection ever found in a single site. For me, the biggest surprise was condition of the shipwrecks. I participated some underwater excavations before Yenikapı. After removing the cargo, we usually had a chance to see three, sometimes five percent of the ship's hulls in underwater excavations. But in Yenikapı, most of the shipwrecks are preserved greatly, as I have never seen before. Thirty-six shipwrecks have been uncovered so far. The so-called round ships for cargo, the long ships or galleys for long voyages, and small coastal seafaring ships. Just one ship remains, Yenikapı No. 37. With the subway tunnel just meters away, Kokabas and his team prepare for the final, all-important dig. First, they mount a camera onto a remote-control helicopter to get an aerial view of the dimensions of the boat. On the right-hand side are the remains of the ancient pier. Where the worker is hosing down the mud is the bow or forward section of the boat. What is most interesting is that this ship is buried underneath the pier, which probably means the boat dates back to an even earlier version of the harbor, before these jetties were constructed. Once the first sections of the boat are exposed to air, Kokabas and his team have a maximum of a few weeks to fully excavate the ship from the ground. In nautical archaeology, it is known as a rescue excavation. The next few days of recovery will be crucial, as every shipwreck gives archaeologists and historians new information about a lost harbor and ancient city that, until now, we've known only from mosaics and books. Constructed in 330 A.D., Constantinople was the largest and wealthiest city in the world, holding onto its power for nine long centuries before its eventual fall to the Ottoman Empire in the 15th century. Key to its trading power was the city's largest harbor, named after the emperor who built it, Theodosius I. The Byzantine historian Jonathan Bardel is a specialist in the urban development of Constantinople. At its zenith, Constantinople was known as the New Rome and the New Jerusalem. If you want to imagine what it was like, you should be thinking of huge colonnaded streets, very impressive vistas, forums with monumental columns built by numerous Byzantine emperors, bath buildings on a massive scale, numerous palaces for the aristocracy and for the emperor himself. The problem today, of course, is that most of that has been lost. Most of it is buried underneath a sprawling modern city. But for the first time in over a thousand years, the modern city is opening up its secrets, but only for a very short window. We want to buy time. Time is important for us. Archaeologists, in the beginning, they were only working at daytime. We have requested from them a lot to work at night also. They refused. They rejected. They said that it is dark at night. But we are engineers. We can make it lighter than daylight. The clock is ticking for the tunnel and also for the archaeologists, unraveling centuries of lost history in record time. The discovery of the ancient port's remains and the 37 shipwrecks could help scientists piece together an important part of the city's history. Why did a harbor so important to Constantinople's growth as a world empire simply disappear? And what will its recovery tell us about life in the ancient city of Constantinople? Before it is paved over and turned into a subway station and a giant shopping mall. In Istanbul, Turkey, work continues around the clock as archaeologists uncover the remains of the ancient port of Theodosius, lost to history for over eight centuries. The rescue excavation of the port's final and possibly oldest shipwreck is underway. But exposing the boat to air for the first time in 1,500 years is a tricky business. Scientists use a special atomizing spray to moisten the wood with the purest water possible. The ship's frame emerges from the mud. So does some of its cargo. What seems like a small oil lamp submerged at the bottom of the boat. Did this belong to a crew member? Or was it merchandise? Byzantine historians have spent a great deal of time trawling through the ancient sources looking for snippets of information about the ancient city, what it looked like and what everyday life was like. The problem is that Byzantine historians generally weren't very interested in giving us that kind of information. What they were interested in was telling us about the emperor's career, campaigns or whether there was a plague or an earthquake or fires. If we want more information, we need archaeological evidence. It's only by marrying archaeology together with the text that we can build a complete picture. By far the most artifacts found at Yenikapi all date back from between the 4th and 7th century. The picture historians are now painting of this period is that of a golden age when the city and its port were at the peak of their wealth and power. Jonathan Bardel's research on the ancient Byzantine port brought him to Turkish 3D artist Tayfun Onur who has been digitally reconstructing the ancient city for over 10 years. Until the discovery of the port, their only sources were books and a few extremely rare and difficult to access maps. So this is one of the earliest maps of Constantinople that we have. This is the Sea of Marmara and here is the port of Theodosius. As a major consumer city, Constantinople needed plenty of harbor capacity to receive all of these ships coming in with imports from the rest of the Byzantine Empire. The earliest ports in the city were constructed on the north side, on the Golden Horn and then as the population grew... And the city grew also towards the west? Towards the west, more harbor capacity was required and so the Emperor Julian constructed another harbor here on the Golden Horn. That was about the middle of the 4th century and then further to the west, the harbor of Theodosius was built at the end of the 4th century. The port was the place where trading ships converged from all over the Mediterranean, Europe and Africa. But what made Constantinople so powerful was its monopoly on grain that came directly from Alexandria in Egypt, ending up in huge warehouses on the port's wharf. Like the bustling markets of modern Istanbul, the harbor was a place where people of all walks of life mingled to buy and sell their wares. Spices, ivory, jewels and clothing regularly changed hands behind the port's walls. It is precisely these types of luxury goods that are often so hard to uncover after centuries of decay. But what makes the site of Yenikapi so unique is its very nature as a port. Artifacts have been perfectly preserved in a muddy, oxygen-free environment, keeping even organic materials like wood and leather in amazing condition for over a thousand years. Like this 1,500-year-old sandal. The scientist keeps it in distilled water to slowly extract the salt from the leather. The water is changed regularly and an accurate observation of the conservation process is essential. This item is one of the most precious, most likely worn by a nobleman. The Port of Theodosius is a treasure trove of personal belongings, including wooden icons, combs and dice from the port's taverns, as well as this child's toy boat. All artifacts from Constantinople's glorious, beautiful youth. The final shipwreck of Yenikapi is now ready for the next crucial stage of the rescue excavation. Utilizing the most modern technology in the field of archaeology, Kokabas and his team begin the incredible task of making a perfect digital replica of the boat. First, they trace each section on acetate, making note of any interesting surface structures. Then scientists use what is called the Faroe Arm to calculate millions of points of reference, allowing them to recreate the ship in the virtual world. Different colors signify what is what, from nails and joints right down to the tiniest scratch. Details on every artifact reveal information and are subjected to research. One month of excavation means one year restoration. Later, scientists will use the information they are gathering to determine the precise date of the ship's construction. But already they have some clues. The depth of where it was found in relation to other artifacts leads scientists to believe the ship belongs to the 6th century, the height of the Golden Age. During this period, the port of Theodosius had no rival, and its symbolic importance to the citizens of Constantinople was something they carried with them every day, in their pockets. As we see on this simple coin found by Ufuk's team, on one side, a portrait of Theodosius himself. And on the flip side, a boat. The Byzantine boat was critical to sustaining Constantinople's commercial power, for trade, but also to fish. Thousands of fish skeletons from that ancient trade have ended up here, in this improvised storage room at the Istanbul Veterinary University. And not just fish, Professor Vedat Onar is in charge of conserving and studying all the animal bones from the excavation. And it's the bones that are providing some of the most interesting clues about life in Theodosius' harbor. ♪♪ Elephants and tigers, and all kinds of exotic animals were brought to the city for the entertainment of the emperor and his people. Most ended up here, in the Hippodrome, which was both a circus and sporting center, as well as the social hub of Constantinople. At this point, Professor Onar's laboratory has received over 30,000 bones. ♪♪ Fifty-four animal species have been identified so far, and a lot of what these bones are telling scientists paint a dark picture of the life of a working animal in Constantinople. ♪♪ The harbor was a dynamic but merciless hive of commercial activity, and animals were just another commodity to be bought and traded, like grain, like fish, even human slaves. With the help of Typhon Onar's digital artistry, the Port of Theodosius reveals itself to modern eyes for the first time. ♪♪ It was Constantinople's largest and most powerful port until the 7th century, and then suddenly, life in the harbor goes quiet. ♪♪ The question is, what happened? ♪♪ Nick Iles is a Canadian geologist here to explore what geological layers in the earth can tell us about the history of Istanbul's ancient harbor and why it disappeared from the city's landscape. This exposure, as they dug down through the tunnels, as we build successive layers in the city's history, then you can see a very dark layer. The workers are on that right now, and that's the initial sediments before the city grew, and then the first human habitation settlement above that about 6,000 years ago. And then in the successive layers above that is recorded the growth history of the city, and there's enormous amounts of fill that have been used to push the coastline further out. So the actual shoreline, many thousands of years ago, was right here, and, of course, it's now way out. It's in the mud of Yenikapi where scientists find clues about what happened to Theodosius' harbor. The dig has revealed a perfect sequence of stratigraphic sediments. Each layer represents a period of history. The black mud is Neolithic times, and the top sandy layer is the 20th century. In the middle is the harbor. Could the harbor have been damaged by severe seismic activity? The threat of a massive, catastrophic earthquake isn't the matter of if for the citizens of Istanbul. It's a matter of when. Technicians have installed over 100 seismic monitors throughout the city. in strategic locations like Istanbul's famous Blue Mosque. Even the tiniest tremors help scientists understand just how and when the next great quake will hit them. People around the world have to deal with some degree of uncertainty in their lives. But if you live in Istanbul, you have to deal with the fact that there will be a major devastating earthquake, perhaps in the next 20 years. How will this bridge hold up? This bridge takes 120,000 vehicles a day. How about the railways, the airports, apartment buildings? Now, to answer those sort of questions requires a lot of work by geologists, geophysicists and engineers. And currently, all that work is being handled through Turkey's National Earthquake Center. So this is where the North Anatolian fort splits. The North Anatolian fort starts somewhere from here. You can see the scarps here. It comes this way and it splits starts here. Constantinople was built on the firing line of the 1,200-kilometer-long North Anatolian Fault that runs east-west, just south of the city. And it's because of this fault that the city has suffered an average of one earthquake every 300 years. Although when they will hit is never certain. We can go another 50 years with no earthquake and it can take place in 10 seconds from now. That we don't know. If such an earthquake happens in south of Istanbul, we figure out that about 20,000 to 30,000 people will lose their lives. Are there parts of Istanbul that would suffer more because of weak rock or weak soil? Most of to this old city because the basin is clay. The soft earth of Istanbul's historic center, exactly where the ancient port was located, makes it particularly vulnerable. So just how frequent were the earthquakes during the lifetime of the harbor? In the Department of Geology at the Istanbul Technical University, samples of the earth's core, taken from the bed of the Marmara Sea, tell scientists what type of catastrophic weather events hit Constantinople in the past. And here we have three coarse sand layers and each one of them, we believe, represents an earthquake event. So during a major earthquake, the seafloor is shaken violently, sediment cascades off the steep slopes and you find it as a record in the sediment core. And at the top, we have these dark organic rich layers. This, we believe, represents a tsunami event that is backwashing the organic material from the land and depositing in the sea. At the harbor site in Yenikapi, geologists find what seems to be a similar tsunami line in a stratigraphic layer dating to the 6th century. Could one of Constantinople's earthquakes have caused a subsequent tsunami wave flooding the harbor? When archaeologists dig at the same depth, they find more clues. Five animal skeletons that were unusually intact. Here, a camel whose neck was twisted towards its tail and body. This must have occurred before the animal died and got cold. And here, a horse found with its feed bag and bridle still attached. Their intact skeletons and the way they were found lead some scientists to conclude they were swept up in a massive tsunami wave. Whether the harbor was destroyed by one big earthquake and tsunami or several small ones is uncertain. But what is certain is that by the end of the 6th century, the harbor's fortunes would take a turn for the worse. At the beginning of the 7th century, the Persians invaded Egypt and the grain supply on which the city had relied for about 400 years was cut off and it was never restored. The city was also devastated in the same period by plague. The population had perhaps reduced to as few as 40,000 people. And it may well be that harbors like the harbor of Theodosius were no longer as well-maintained as they had been in the earlier periods. Nevertheless, the harbor would survive for another five centuries, although greatly diminished. What happened to the port of Theodosius after the Golden Age? And why were the majority of shipwrecks from these later years discovered in a cluster on the eastern side of the port? What will they tell us about Constantinople's busiest commercial harbor and its eventual disappearance from the history books? Archaeologists have been uncovering the secrets of Constantinople's lost harbor and its 37 shipwrecks for almost five years. And now the final boat, known as YK-37, is ready to be moved inside. Salt is now the archaeologist's biggest enemy. YK-37 will be immersed in a huge tank filled with distilled water that slowly leaches the erosive material from its wooden timbers. The process takes five years to complete and eventually it will be ready for the final stage of preservation when the boat is infused with polyethylene glycol, a wax-like ingredient that will harden and preserve the fragile wood for all time. In most cases, penetration of chemicals takes considerably long time, five, sometimes ten years maybe, and we need to control and monitor all process and keep other organisms out of timbers. Already, ships are allowing scientists to see just what the Byzantine fleet looked like 1,500 years ago. And one ship in particular, YK-12, has a unique story to tell, one that could shed light on just what happened to the harbor in its final years. It was found with its cargo still on board. There was a compartment close to stern which contained the personal belongings of the vessel's captain. The casserole bowl, beaker, and cherry stone inside a reed basket. For Ufuk Kokabas, the cherry stones provide an all-important clue. Cherries ripen between May and June in the Marmara region, and this is the time of year known for its sudden storms, called kakak. The big question is why all the cargo was still on board. I guess it must have been silted up immediately right after some kind of natural catastrophe. Because if your ship sinks in the shallow water of the harbor, you would rescue your stuff by diving. Scientists now believe YK-12 sank in the 10th century, and that most of the boats discovered from this period also sank in heavy storms. By this time, half the harbor had been abandoned and filled in with silt, which is why shipwrecks from this period were only found on the eastern side of the harbor. Jonathan Bardel and Typhoon Owners Quest to digitally replicate the Port of Theodosius is almost complete. At the Museum of Archaeology in Istanbul, they view an important and incredibly rare historic source, an illustration of the harbor's walls that will give Typhoon precise details of how the exterior looked. So this is the very west end of the seawalls. It shows the port as it was in the late 19th century, so before the coastal road was constructed and much of the walls were destroyed. It's a unique record, and we can't expect to get much closer than this to what the port looked like in its original Byzantine state. The illustration's rich textures bring owners' digital image of the harbor much closer to life, allowing both him and us to travel back in time to the harbor's golden age. In fact, one part of the port's ancient seawall still exists, cut in half by a six-lane highway. And with one click of owner's mouse, the harbor walls reappear in their original form. This would have been the view the ancient seafarers had when they finally reached Constantinople after weeks or even months at sea. In the end, scientists and researchers agree it was no single catastrophic event that destroyed the port of Theodosius. Centuries of damage by earthquakes, tsunamis, plague, and invading crusaders took their toll, and by the 1400s, the harbor was left to completely fill in. Our final view of this once-great landmark can be glimpsed in the map of a Venetian traveler from the 15th century. We've got part of the map of Giovanni Andrea Babasore, a Venetian cartographer. He's got the port of Theodosius here, and you can see it's an area that's entirely enclosed by walls, and inside we've got trees growing. By that stage, the harbor was almost completely out of use. It has taken archaeologists over six years of non-stop excavation to carefully extract Yenacapi's secrets from the earth, before Constantinople's remarkable historic harbor disappears from Istanbul's modern landscape. And with the last shipwreck now safely above ground, Hussein Belkaya is hoping that maybe, just maybe, the subway tunnel schedule will get back on track. Whenever they discover something in archaeology, I feel sorry for the citizens of Istanbul because the project will be delayed some more. But as a citizen of Istanbul, I feel proud. I am excited about the new discovery because they are rewriting the history of Istanbul. This is fascinating. I like that part. The construction of the tunnel under the Bosphorus should really be seen as just another phase in the harbor's history, and it's precisely because of this new phase that we've been given the opportunity to learn so much about life in an extremely busy and important area of the city of Constantinople.