for power and profit plummeted an entire continent into chaos and violence. this is the journey back into the history of slavery. our documentary series slavery routes starts march 9th on g.w. . you're watching tomorrow today the science show on d w coming up. a sensational find in lake constance archaeologists dive into the past. and mexico an inventor is building houses as have seen weeds and find out how to turn carbon dioxide into plastic. 170 large piles of stuff hens in

a line running along 10 kilometers of shoreline for millennia they went unnoticed submerged in the waters of lake constance in central europe they form a remarkable manmade monument. all told it consists of more than 120000 tons of stone about as much as one inch of building the cathedral in cologne . if each stone weighs 2 kilograms on average then the structures at the lake consist of $60000000.00 stones. today it would take more than 8000 truckloads to move them but these were all transposed it by hand. the latest analysis shows that they must have been put there by humans research teams have been trying to find out when the mysterious cannons were built and why. someone 2019 a team of archaeologists and geologists sets up a tiny drilling. platform on lake constance their aim to find out when mysterious

cans on the lakes bed were built. the geologists flavio and so messy from the university of and his team are experts at geological drilling they want to take samples from deep inside the lake bed to determine the age of the stone piles resting on it 1st the rig has to be anchored and then maneuvered into a precise location using g.p.s. . and geologists combine an impressive wealth of knowledge. the whole 5 hope with a drilling that we can determine the age of bit more accurately is it really prehistoric and if it is prehistoric was a made during the bronze age or the new olympic. team hopes the drilling samples will allow it to form a better picture of the sediment by the can. we chose the drilling sites that

allows us to get down to the layers which will show us how they developed over time . the scientists used ground penetrating radar measurements to select the site they highlighted all the sediments on which the cams lie if the research has succeeded determining the age of the sediments from a drilling sample they can deduce the minimum age of the can. the main tool of the experiment has a plastic tube which will be driven down by the trail through the sediment layers. in. the drill casing with the plastic pipe inside just brought into position. time to start. using how many drilled they drive the device 6 meters deep into the bed if they like.

once they reach the desired depth the scientists hold the drill back up to the surface with the layers of earth trapped in its coal. it's all running according to plan the sediments packed solid inside the plastic sheeting. and it's rough. now we cut it into metre long sections then it goes off to the lab where we get to work on it. the sanctions contain thousands of years of lake constance history and maybe a hint about the age of the mysterious cans. a few days later in the cool room that byrne university's geological institute and so met he and his team take a closer look at the sediment inside the plastic tubes they've already determined the most promising layers. what we've laid out

comes from a 6 metre deep hole so here we have the lake bed now and in 6 metres depth formulate bottom maybe a few 1000 years ago suitors have cited depth of about 3 metres according to the radar picture it has to be here somewhere we expect to find the form of lake bed on which they built the mounds. so the idea is the ice cut through that and see if we can find any organic material we can date with the radio carbon method. in the laboratory the plastic tube sections cut open lengthwise. the sediment layers a cafe separated. put it down back ok. in front

a little pressure. pull it back. here. perfect wonderful. and exact image as the cools interior hopefully it will show enough traces of organic fossils that can be used to gauge the lay is a. if you zoom right in you can see lots of black spots in the core samples we hope it's organic material plant remains in sufficient quantity to date yeah now in order to isolate the tiriel we're taking individual samples from the core. because. if there's no organic material it won't be possible to carbon date the samples. fortunately the geologists managed to isolate a few minute would fragments and some plant remains.

as cool we found quite a bit not too much but with enough small bits and a large one for us to take them into the sea 14 lab and ask them to date it so you know all. the sophisticated procedure is needed to date the fragments and along with them the cans themselves because she data and his team are watching out for telltale traces of the carbon isotope called c. 14. to see foreseeing can be found wherever this carbon means in any living materials but also in part in carbonaceous minerals any way you find carbon you'll find sand 14 is not too far. in a series of steps the samples i cleaned and prepared for measurement. if their carbon

14 contents can be determined then so can they each. of the age of a sample can be determined by tracing the decay of its c 14 component we know the unique specific carbon 14 content of a fresh sample we can compare that to the content of an old sample in which the sea 14 has decayed over time the extent of decay tells us how old the sample is. the samples are ready for testing only a minute 400 micrograms that's not point 0004 grams left but that's more than enough for an accelerator mass spectrometer the machine breaks the sample down into its smallest individual components until finally only the c 14 atoms remain frozen because she doubts that's the key to the samples age. but we can observe here and we can see that this sample comes from a period between 3403650 years to the sea so roughly speaking the

sample is some 5 and a half 1000 years old. 5500 years that means the cancer from the neolithic age. there's no holding back the archaeologists now they take a dredge out onto the lake and bring part of one of the stone piles to the surface for investigation in part of the whole archaeologist was lloyd makes a promising find. there was a steak on this block once the really exciting thing is you can see the remains of the steak and the sediment. it's been moved but it's still in proximity and that shows us someone drove a stake in down there and that it's not just driftwood and because it's been shaped we can assume that it was driven into the ground at the same time as the karen here . you know. the excavations promised to reveal more secrets

concealed in the camp. to meet the humans who most likely built the cairns in lake constance we would have to journey back in time past the middle ages the roman empire before the celts before the bronze age back 5 and a half 1000 years to the neolithic age. at a time when europe was vastly copulated. the lakes near the alps would have been lined with houses on low still. the population might have seemed very useful by our standards few people lived to old age. life was simple and hard. people farm the land raised cattle and went hunting. they only survived by living in communities.

mortality rate meant that women as give us of life had a special status as illustrated by these clay pots with moldings in the form of breasts or this wall sculpture one of the oldest and biggest in europe it 2 features clay breasts. belief to depict the female ancestors of various lineages. the famous mural was also found by like constance. there is evidence suggesting that a european network already existed in the neolithic age goods and materials have been found in the region around lake constance that were imported from across the continent including copper ceramics and even jewelry. another thing that people from across europe appeared to have in common already was an appreciation of megaliths large stone manmade monuments such as stonehenge in england. and qana in brittany

but now europe has another neolithic landmark in lake constance dubbed this with stonehenge. of course the scientists want to know what purpose the stone pile cept maybe the people in the neolithic age built them to celebrate the summer and winter solstice the piles are lined along the sun's perm. bonfires on the piles as possible ritual. it's just one of the many riddles yet to be uncovered about the find in the lake. another remarkable find is this neanderthal skeleton that archaeologists recently excavated in the shadow of dark cave in northern iraq. it is around 70000 years old the position it was found in suggests that it was buried with care. the

left hand bend towards the head the right arm lies at an angle on the chest the head is bedded on a stone. it's the best preserved discovery of its kind in a quarter of a century the researchers hope it will tell them more about the burial rituals and the society of our neanderthal cousins. we also do you on facebook what you think archaeologists might discover about 5000 years from now. when indonesia reckons they'll find devices they think are junk like mobile phones computers and. nicholas is pessimistic saying that they won't be any archeologists in 5000 years because they won't be any more people. alphonso from mexico jokes that the archaeologists in the future will find all those socks

speckled lost in the washing machine. and sherry says that the main thing they'll find from us is plastic lots and lots of plastic along with discarded phones and other devices. indeed all the plastic we produce today is likely to stick around for hundreds of years. each year around $8000000.00. more tonnes of plastic end up in the sea and moved around the planet by wide ranging ocean currents currents that play a key role for life and our planet. but how do they arise. in el salvador sent in a question about that is. what causes ocean currents they flow like vast rivers with no water driven near the shore by the rise and fall of tides at

high tide water flows towards the coast at low tide it flows away from it. surface currents in the ocean are propelled by strong persistent winds. while further down variations in temperature and salinity drive deep ocean currents . cold salty water is denser than warmer water with a low salt content so it sinks towards the bottom of the ocean. the speed of the water flow depends on the topography of the seabed. the variations in temperature and salt content also cause a phenomenon known as the global conveyor belt it's a system of currents that transports water around the world. ocean currents crucially affect climate for example the humboldt current brings cold water teeming with nutrients from man tock tick to the collapse of silence for 6 months of the

year. they feed the tiny plankton and algae that form the base of the food chain providing sustenance for swarms of fish and also for the marine in quanah the only lizard that lives and forage is in the sea. on land meanwhile life in these months is hard there's hardly any rainfall wildlife including the galapagos giant tortoises have to embark on pair. journeys in search of food but in the other half of the year food is available in abundance that's when the wet season comes with the panama current bring in warmer waters. this current isn't nearly as rich in nutrients so much of the island's marine life heads off to colder climes aquatic animals that remain have to make do that finally climate change is taking a toll on ocean currents exactly how is the subject of intense research.

as we heard ocean currents are critically important for marine life cold oxygenated currents are a source of life under water. but sometimes the local ecosystem tips out of balance when one species takes over. for example a kind of seaweed. that's in mexico and inventor has found a way to use it. brown seaweed on the mexican coastline a disaster for the environment and the tourist industry but for all my vazquez it's free building material. we extract all the water and remove the garbage we continue that process until the seaweed itself starts to produce a kind of organic clay and becomes a hard resistant mass. which. he

produces his own bricks that is 60 percent seaweed a 1000000 tons of the saga some macro can be washed up on the yucatan peninsula over the course of one year the problem has exploded in the last decade. it comes from all the pollution caused by human activity all those chemicals washing and cleaning agents that end up in the sea. the algae feed on causing them to grow and multiply. in every day for our nickel rivera and her team clean up the beaches before the seaweed starts to decompose a process that would release all fear of acid in toxic gas is devastating to the coastal ecosystem. it's important to support initiatives like on mars where. we just collect the seaweed we're happy to then pass it on to others who can do

something with it the main thing is for it to not be polluting the environment. that cares and his teen seaweed with mud and other organic materials and then stomp on it with their feet to press it together it takes around 20 tons of seaweed to produce one house he's actually a gardener by trade and initially used the seaweed for compost it took a while to get the consistency right for building blocks and to ensure the bricks would no longer release toxins. since i 1st came up with the idea we've been improving the formula every day and now we have a patent and we have the best organic product for building a. vast coast donated this house to a family who lost their home in a fire one 3rd of the local population lives in poverty including one who could go mares and has 6 children. now this house is cooler than our old one in the sun it's

very hard many of my neighbors now want to. go like that or see. the circus and brakes are said to be more robust a word and cheaper to produce than cement they've generated huge interest no noticeable really or no i haven't really invented anything yeah i'm just giving back to the earth what belongs to it as a problem into an opportunity my. experts see great. attentional in his idea hotel chain in mexico has now started a project with its aiming to build part of our is sought with some breaks foreign companies are also showing interest and there's certainly no shortage of the seaweed on mexico's caribbean coastline. there's so many clever ideas around for turning garbage into something valuable like making elegant clothes out of plastic waste. collecting beverage bottles and using them to

build boats. or even houses. and recycling plastic to lower c o 2 emissions. but now it team of researchers wants to make new plastic out of c o 2. plastic circuit make the class nerd a multi-talented who no one really likes. there are some good reasons for that even though plastics have the answer to all kinds of needs household as construction material in cars or aircraft. plastics are carbon based substances synthesized from hydrocarbons from crude oil so they're not sustainable that's exactly what these 3 chemists bear which are no cost of gertler and voter like not want to change. plastics has been based on fossil resources and fossil resources

are finite but there is one source which is infinite and that is carbon dioxide. carbon dioxide the greenhouse gas imagine simply getting the carbon for our plastics out of the air thereby reducing oil consumption and atmospheric levels of c o 2 to problem solve that one fell swoop. but the researchers not only want to make c o 2 based plastics they wanted to be easily recyclable let's do what they did. and go right back to square one. a typical plastic consists of long molecular chains of carbon atoms with lots of hydrogen atoms not much more but to actually make a plastic the constituent molecules have to be induced to bond properly. the hydrocarbons from oil are bursting with energy and looking for any excuse to react with something. the c o 2 molecule is in there it's unreactive a regular couch potato of

a molecule. which. seals why it's the c o 2 is a decidedly sluggish molecule it needs apologetics just like in real life to a new job and get the lazy dog moving. in the reagan home to believe that you need a catalyst to bring the 2 together and get a bonding started it's all to form the final compound. does the movie. and just what is this catalyst well it's not a magic potion but it does lower in efficiency enough to allow the 2 partners that have a certain affinity to hook up properly. it's like at a party the guys want to dance with the gals but are too shy to ask but when the d.j. puts on the right music then push everything comes together music is the catalyst. and this white powder is the catalyst for our reluctant c

o 2 the result of hears of research it persuades carbon dioxide to react with other chemicals. the result is this viscous fluid a polio on a palm eric molecule incorporating numerous oxygen atoms for the polio is used as the basis for a variety of plastics such as polyurethane foam for mattresses derived from c o 2 from the app. sphere. you know i'm safe behind our innovation was to be utilize it as a kind of technology platform that way we can easily broaden its spectrum of occupations bring us into areas like elastic fibers there's a fast and. that means clothes could also be made of c o 2 in future but clothing doesn't last forever what happens then here the new plastic has another advantage the c o 2 it contains x. is a built in breaking point and they glow in the polymer to be split up and then easily

recycled but doesn't work with pure carbon chain plastics. vision is to become more focused on circularity in 10 years time we'll be seeing many more chemically recycled products in the human like it's got a good way towards our vision of a circular economy. but. the goal is to make our resource footprint smaller to move away from a linear economy which turns resources into waste to a circular one based on recycling. the problem is right why don't you. do you have a science question that you've always wanted answered it we're happy to help you out send it to us as a video text or voicemail if we answer it on the show we'll send you a little surprise as a thank you god and just ask. get in touch with us on our website d.w. dot com slash science or drop us

a line on twitter and facebook. next week and i'm usual storage system for sustainable energy at gravity battery its inventor wants to build a tower of stacked cement blocks to store excess energy how does that work join us next time to find out until then by. get.

outta. overcome boundaries. changing the world with. no words required. but a full body in good. company john thomas. march 24th. coming up on w. . the force is with you young man why.

not i just i. must you are muslim are not all. the bad at the official lightsaber tournament in france the world china is showing what they're made up above may the force be with them your. it's. a 30 massacre. on a mission to save the. marvel comics started in 1039 they created a vast empire of superheroes with human weaknesses. have had their share of closures and the moving story coverage

a little more of course march d.w. . international women's day. we tell the stories of women around the world. their rights their struggles and their mysterious. man who never thought hard for an independent self determined life. unafraid to speak out africa big develop a galley given grace and chances next big boys. and afraid to stand out. not just on international women's day. i'm d.w. . frankfurt. international gateway to the best connection self road and trail. located in the heart of europe you are connected to the whole world. experience

outstanding shopping and dining offers and try our services. biala gassed at frankfurt airport city managed by from. this is they doubly news and they top stories. there have been fresh clashes between great border gods and migrants trying to cross from turkey the e.u. has told my friends the border will not be opened and has accused ankara of using them for political breaks. 21 pay.