One of the World’s Oldest Submerged Ancient Cities Was Found and Explored in Southern Greece

 well my original aim with the the Pavle petra project was to record it in as much detail as possible and it was first surveyed back in 1968 by team from the University of Cambridge using measuring tapes and just snorkels from the surface and they did a fantastic job but the reason we've gone back 40 years later 

was to use new technology and to use the cutting edge of technology every year and it's developing so quickly that each year almost we've used different techniques and probably no powerful opechee is the 

most surveyed bit of seabed in the world and we've applied probably more techniques to than you know than anywhere else and every year I think this is the best serving technique no actually this is the best of all no no we've cracked it but no actually I honestly believe that we have a technique which is going to I 

think revolutionized the way people do underwater survey it doesn't just work in shallow water works in very deep water as well and what it gives you is a photorealistic impression of the seabed I mean just as the seabed looks I mean when I started the project I couldn't have hoped for the technique that we've 

now got and essentially it's it's a technique that's been developed by the Australian Centre for field robotics and and it's a stereophotogrammetry technique and what that means is it's a it's a system that uses stereo photo cameras and over the site to create a map a photo map of the site but not only that it 

adds 3d into it and for the two different perspectives from the cameras equally they can attach a multi beam system to this equipment which is like an acoustic system and which will give you a three-dimensional impression of the seabed so basically you mesh the photographs together with the 3d mesh 

and you've got a 3d photorealistic surface you can go down and you can you can examine individual shares on the seabed and the resolution is such that you can actually identify them and then you can pull out you know to look at the full site and it over eight hectares so really it's it's for me it's just 

phenomenal and the nice thing about the powerful Petre project as we've used lots and lots of different techniques so we have lots of comparisons to assess how accurate a particular technique is and a base level that we used was M simply using a total station that's a laser and method as a machine that shoots 

a laser to prism out in the water and it's exactly the sort of thing that you'll see people surveying and motorways with or you know doing building surveys with you'll see them you know in every city in the UK and we use that in the water using just a slightly longer pull and divers are in the water but that's 

given as a baseline a very accurate baseline to within about five centimeters as a level of error for the whole plan and that's given as a plan of the city but it's vector lines it's just lines like you know you would you would draw with a big if you might a big digital pain it's a two-dimensional plan but it's also 

got the 3d information so you can look at it in 3d but it's just lines and what this new technique has given us is the actual photo realism which we can overlay onto that and check the accuracy of it because we've also used other techniques we've used acoustic techniques which work a week I'll be bit 

like an laser scanners and you get point clouds so you get three-dimensional point clouds underwater and we used a technique called sector scan survey and developed by a company called Khan's Berg nasal tech and it was a group from America and Nautilus marine grouper came and did that for as last 

year and that was fantastic I mean very very quickly you can get a 3d point cloud of what's underwater so you can find things you can get two dimensional maps from it very very quickly but the reason the new technique is so good is because it's photorealistic people can look at it straight away and go oh 

wow that's a you know that's a that's a submerge city you know what's been exciting about working with the BBC and bringing them on board is this year we managed to work alongside CGI movie professionals these are people who normally work on films like Star Wars the prime focus they're called 

and they are actually working on Star Wars Episode one making it 3d at the moment but anyway and so we were actually able to work alongside these people in the field I mean normally what would happen and when there's a reconstruction as the archaeologists were going to the work and then the TV people 

would make the reconstruction there be no connection between the two but what we were able to do because we were getting this 3d photo realism in the field was actually at the same time have the guys from the the CGI company build the walls and work with the archaeologists so for I think for amongst 

probably the first time we have a we have a data-driven reconstruction it's based on the archaeology and it's produced by team that worked with the archaeologists well essentially what we're doing is bringing a few thousand year old city back to life you know something that hasn't existed for a few thousand 

years and that's the exciting part of it MIT's it's it makes you change your view of the city and in a way that you would have done just working on it because we had these guys working with us and I was looking at walls and us thinking well this this room could be something different this is this is a house 

but this is a building of a slightly different function and we start building the walls and looking at it and a way that you don't see it underwater you can come away above it you can look at it you know you can really examine it I began to kind of change my interpretation of certain buildings and you know the the 

CGI team became part of the of the research process and there was a quite an exciting synergy between the CGI guys and the archaeologists in the field well this is the third year of what we hope is going to be a five-year project and we're in the process now of applying for the next permits to start and 

excavations on the site and this year we carried out a couple of quite small test trenches just to see if this deposit surviving on the site thankfully what we found was there's actually still quite a lot of deposit and to be excavated for example we were finding the top of storage vessels the top of pith or 

storage vessels which we think were imported from Crete interestingly enough but showing networks of contact throughout the eastern Mediterranean but the top sitting in the in the seabed implies there's a meter 2 meter and a half of deposit still to be excavated underwater so I think the next phase is when it 

gets really excited that's where we start to really start finding the material and then hopefully because the site is a submerged site because it's underwater and we should be getting organic items wooden items the kind of things that don't survive and land because it says you know underwater as a site it's it's 

an area that lacks oxygen and particularly when things are covered up with sand you get a nice oxygen-free environment organic food remains can survive you know rope could survive and baskets could survive from the Bronze Age which would be a really thrilling find we'll use the stereophotogrammetry 

to record the trenches and three dimensions as we're excavating them and we trialed this this year as well the idea that you you excavate a level a layer and then you do the stereophotogrammetry technique in 3d then you excavate the next layer you do it again and then the next layer and ideas you can go back 

and you can almost read excavate the site and we're recording exactly what we're doing in three dimensions as we go through the deposits so we're creating a record that other people can then go back and use and can go back and analyze and perhaps even reinterpret you