it's very beginnings until this very day she i'm interested in shaping. this is the journey back into the history of slavery and i think we will truly be making progress when we all accept the history of slavery as all of our history. our documentary series slavery routs starts march 9th on d w. by roy it's venice shouldn't really exist with its 124 islands and countless bridges and kells this city in northern italy was built in the middle of a march. it's proof of human or dayshift snus and our ability to muster

nature. shot down thinking that there are many beautiful cities in the world but venice is in a class of its own. every year more than $13000000.00 tourists come to marvel at the palazzo surround the grand canal. these stately townhouses are on to take several masterpieces built using techniques that are unique worldwide. then seems to float away to slee over the water but in fact the entire city stands on a forest of wooden tiles 10000000 logs with driven into the mud contrary to all prevailing rules of evan construction. the architects of the time conquered the lagoon to build one of the world's most extraordinary cities but the water is a continual threat even today. then this is palaces with. stan the danger posed by the war. will they gradually sink.

the history of venice began more than one and a half 1000000 years ago in the last stretch of course in the northern mediterranean on the adriatic coast of italy. and again on the southern edge of the else is 50 kilometers long and tension on it has winds. at one time it consisted of brackish water sand and mud and inhospitable place of little interest to anyone. then in the 5th century coastal inhabitants discovered the lagoon as

a refuge. of the lagoon was a natural fortress it was very difficult for enemies and their sailing ships to find their way around here but getting only the locals knew all the channels so they didn't have to build walls or. even architectural historians like tonight. know very little about the 1st welling's built this area. that is imagine there are just a few paintings which give us an idea of what things may have looked like on riata island sound the core of the settlement with that straw thatched wooden huts it was located on reality it was the cost of the only offering of an eye for the 1st buildings in ancient venice were built on the most stable areas because of the name re out o. comes from alto which indicates a high location by the river with the name of the district or so dura includes the word for solid the early city was built at sites like the 3 of us.

that its beginnings was still centuries away from the venice of palaces and bridges we know today. the 1st one. asians lived on small islands separated by books where. each island had a small village with a similar structure essential an open space with houses a ground s. and a church in the middle. with the sleeve to give you that explains why there are so many churches and small squares here because they were the centers of these altar micro towns treat all. over the centuries the small islands were linked by bridges which were often built over the water at strange angles. in the 2nd century building space gradually

became scarce so. the problem could only be solved by developing new manmade areas but that was far from easy to bet if that occurred in consists of sediment and much crisscrossed by numerous water courses building ground that was in constant movement. in one of the on a hill logically speaking this is neither solid ground nor the sea the ground varies considerably on the one hand almost it is characterized by the sand which the rivers transport from the land. out in the reeds there are pizza oils have a totally different consistency so venice is built on various layers of different density and that makes for problems why do we see so many slanting church towers. because they are not standing on just one type of substrate.

venice's church tallis leaning to one side but they do not topple over. so how did architects manage to build on this difficult ground without the buildings collapsing. the secret is to be found in simple wooden posts. hundreds of thousands of them were driven into the better for the lagoon. at depths of 3 to 8 meters below the surface architects had discovered a layer of sedimentary clay known as kind until beneath the mud. by driving the posts into this layer of clay a stable building foundation was made possible. civil engineer dino to morley explains the principle was the part it will be to in order to stabilize the building substrate piles were driven into the bed in each area. it sufficient piles are used in the areas then so that with water the mud between the piles becomes

compressed and thus more stable than everything outside the area the piles keep everything together and prevent the substrate from being washed out that's the principle behind ground stabilization of the body. in this way the venetians created man made areas on which an entire city could gradually be built. because architects had discovered that the wooden piles did not bronze in the mud. the poles. underneath the buildings in the mud. that prominently in oxygen spring environment none of the microbes that would normally think a wood can get into that. the wood undergoes

a process of mineralization it turns rock hard and remains intact for centuries. the most famous the nation buildings were constructed on this building ground of mud and wood. st mark's square with its bell tower stands 110-0000 wooden pylons. the foundations of the relative bridge rest 112000 pilots. and more than $1000000.00 wouldn't trials were driven into the lagoon for the impressive lesson to tip us silica which is built of model. there are between $8.10 i wouldn't piles were square meter with the entire city stands on an incredible number of. it's rather like the opposite of

a forest. here the tribes are function like roots and it's. all in all an estimated 10000000 wouldn't piles have been driven into the a large proportion of what used to be the northern italian forest. predominantly oak and large trunks from the surrounding regions was shipped to the lagoon to create extremely expensive building ground. for the foundation which accounted for half the construction costs the other half were on the buildings themselves so the section under water was just as expensive as the part we can see. of. all of them this is 400 stand on these unique foundations. from the 11th century these architectural masterpieces were built on the constantly moving bed of the

lagoon and the sandbags in order to build them the architects had to come up with something special because they faced several times at once. it means providing protection from the rising and falling salt water. designing buildings that were as light as possible. and building on a moving substrate. the solution they came up with was brilliant they placed a wooden construction on the piles and weighted down with several layers of bricks . on top of this they go to surround a white stone from history on the adriatic it formed the 1st line of defense against the salt force. that deals with the interface between the water and that that resists an infinitely long time because it's not probable to the salty water. the resistant strain stern is unaffected by the brands and full of the

siebel said. the highs of this protective wall corresponded to the tidal range in this way the water was prevented from coming into contact with the most sensitive load bearing brick walls. the good reason the palaces on the stone base were designed with a maximum of 3 fields. they understood when they were building that they couldn't make it to have a because they knew that it was all relatively friends in geological tallis that still contacts and causes subsidence. slender columns and large windows in the efforts to build with minimum waste the architects created the special venetian style elegant and graceful. but despite the

lightweight construction method by no means had all the challenges been overcome. given more then because the movements of the ground in the water here are so variable the buildings themselves could not be too rigid. but here to the venetians came up with clever solutions like using special regional building materials such as lawn mortar. it was used in the construction of the brick walls applied as a cement substitute it has the advantage of remaining flexible. not sure saying that obama a long time was probably the most important construction material because of its adaptability so it doesn't get as hard as cement architects always wanted to build what they wanted and how they wanted not to be restricted the materials. to remain flexible in the future to bhavna division done with done. that also applied to the

flooring between the stories. they used wood which is also flexible material. another trick and should flexibility where the wall and the floor join. the beams were set in the walls in such a way that they could always move within them. flexible and supple venetian buildings alike living organisms which adapt their form to the vagaries of the moving substrate. today the traces of this constant attempt taishan are visible in many places in the form of distorted facades and their cracks appear inside the buildings as well. although there have been

a couple of instances of subsidence some facades have become distorted and tilt slightly but not one of the venetian palaces has ever collapsed with the crawl given that. this is architects constructed the building so well that they can even withstand the frequent earthquakes in the region. i remember my father in law telling me about when there was the earthquake in 3 only in the 1970 something and venice felt the shocks of that very strongly and where we live as very big windows you know with lead holding the panes of glass and he said that the windows just moved like the sails of a boat and then came back in place not one of those little panes the crack then fell out. there is a well. in the courtyard of every plant served. by developing

a sophisticated system for collecting rainwater venice's brilliant architects solved the problem of the city's drinking water supply. water flowed through these holes in the ground and into the underground chambers filled with extremely fine sand. up to see things through the sand the clean water then rose again in a well shaft. in this way they also wanted to conduct the water from the gutters into the wells and it really was an ingenious system one unparalleled worldwide you're all these wells were still in operation in venice until the early 20th century. every square in the city has a well in all its architects created $900.00. by the late 15th century venice had 170000 inhabitants more than ever before the since he was

in its heyday thanks to its powerful fleets of ships built in the queen's shipyards venice dominated commerce in the mediterranean region. the city goes on water was totally in its element like a fish and also. the venetian is have created an architectural jewel in the north in the good. but nature was to turn on them in a dramatic way. as a result of human interference in the green system of channels to facilitate shipping new dangers began to threaten the blossoming influential city. the earth was having a serious effect on the bed of the lagoon and the titled water levels. the natural balance in the good it was under threat.

centuries later venice is still a proud and beautiful city but over the centuries the lagoon changed completely. shipping traffic and industrial utilization increase dramatically and left their mounts in the course of industrialization a 1000 wells was sunk in order to access the groundwater beneath the bed of the lagoon. in the 150 s. up to 40000 cubic meters of water removed every day. civil engineer pietro describes the consequences for venice these generate a. decrease of the pressure. and when the pressure of the

trees in the bay using the mentoring raising the basin is these producer compaction off the sidelines and warning of the land surface right now we call it subsidence land subsidence. as a result of this learn subsidence venice subsided by 14 centimeters in only 30 years. after a disastrous flood and $966.00 the practice of pumping up the groundwater was discontinued. but the damage to the city is irreparable the last 14 centimeters can never be regained global warming and rising sea levels are increasing the threat and have already seen the water rise by a further 10 centimeters. in all the water is now $24.00 centimeters higher up on the buildings than at the time they were built and that. left visible traces.

most of the affected areas can be recognized by the green zones on the buildings this is where the water rises and falls with the time it's. it's not major floods that are causing the greatest damage to the city but to try to change it. from local if you so water comes and goes incessantly. with each new time to the salt water is now also reaching the bricks another fine the architect centuries old preventative measure has the ring of history in stone can no longer protect the palaces from the roofs or. the water is always against the break and the bricks are very powerful and. leaving behind the souls which crystallize and as salts crystallize they expanded

the body and 12 times and that is a very kind of slow way you can say exploding brick. the sun towards her is also attacking the lawn most of between the bricks loosening them and weakening the entire building structure. to provide more stability more and more steel barry is a being erected in the city's canals. today one in 3 venetian finance is damaged and a need a friend of a ship. and that is not only the result of the daily tide change much about its are an even bigger problem they stir up the water above and below the surface. just get us out of the back of the constant boat traffic is very bad for the masonry. the boats propellers churn up the water which a dish. only a road to the wall. by once the masonry has been weakened. the water also

impacts the foundations on the ground. and old it is boats are always travelling past the building. in the back of it's the number of boats and the frequency of boat traffic that is threatening the walls. gets into any cracks in the brickwork and thracians the entire building structure it also loosens the compacted earth between the piles the centuries old foundations on which the buildings stand in the attempt to limit the damage the city has introduced a speed limit for water taxis. to launch cruise ships which head for the diggin every day are a further problem. these big ships move huge volumes abort a you know that's our communities principle there's still

a body of women at the bottom of this ship that move and when they're in their power to get this thing over the last will narrow the scope of the local level rises and then goes down again with the conflict of the ship it's a wash water that moves within you know over tens of seconds or minutes and that's very detrimental to the building foundations. subsidence of the beds the rise of the water level and the waves created by boats and ships mean that venice is threatened from all sides. the only way to save the cities valuable buildings is to drain the canals for basic restoration work but that's must be done with great care. but in the note that the she took a lot of the work only takes place and drain sections with a maximum length of

a 50 meters. draining the canals leads to a settling of the geological layers and that can result in damage to the neighboring. so a canal can be drained or longer than 3 months. today more modern methods are also being applied in order to stabilize the walls chemicals are introduced into the lime mortar. they prevent mortar getting into the bricks all these measures are carried out by have and. that is why restoration work in venice is more expensive than elsewhere at present the city has no more than 2000000 euros a year available for preserving its buildings but the actual summer needed is 13000000. the water to which the city owes its uniqueness and its wealth is now

turning against the venetians. today one 3rd of the ground floors in venice are uninhabitable. and rising water is threatening the buildings more and more often. global warming which is resulting in a gradual rise in the sea level will intensify this development even more. so the stance of kidneys venice is destined to go under that is not my prediction but that of people who deal professionally with marine and climate issues in the prohibition has been down from the and often essentially the same the sea level rise may let's and between 204-050-6070 meters. the demise of venice no longer seems to be merely a pessimistic scenario. consolo once again the engineers here italian i. architects and engineers is called for to save the city.

or. the most a project is an elaborate and expensive attempt by the italian authorities to say venice. concrete foundations weighing many tons have been sunk at all 3 looking in let's. get in there and flood gates at high water these can be raised as far as the water level requires. there is no doubt that if it is ever completed the most a project will be an engineering masterpiece. but skeptical voices warn against euphoria. in most usa the most a project is important but it's not the sole solution it's inconsistent i believe to want to protect the city from super floods without at the same time protecting

it from decay or. that is why another idea is to raise the subsided bed of the lagoon and with it the entire city. what sounds like a crazy plan was developed by researchers at the university and neighboring powder well. we don't work. on our own ass souple our shape we do know they own it or don't you know meters and we inject the water into it quite obviously we select the knocker 1st located between 601000 meters below the moon walk on. raising such a huge area with an entire city on it is an ambitious enterprise which no one has ever attempted to form the plan is to pump 50 liters of salt water per 2nd thing. the wells and into the substrate over

a period of 10 years researchers have calculated the bed of the lagoon could be raised by between 20 and 25 centimeters. the water level in the canals with tensing but the same amount but the plan is not without risks you cannot do it. in a shorter style we don't want people to generate any any structure. and for this reason we have to do to inject the safety rate. raising the bed of the lagoon would recover the last $24.00 centimeters the project is still in the planning stage research is awaiting full funding for the 1st comprehensive tests. a little truth possible to save the masterpieces of a nation architecture from the consequences of human made problems. no one wants to see this city go under venice nice visionaries like those who built

it people who will think the impossible in order to achieve something magnificent. plan . more home. it's all happening go to visit a few. sure link to news from africa around the world. your link to inception stories and discussions. hello and welcome student news i'm feeling comes that night from the new gemini from the news of easy and i would say

d. deputed close the traffic come join us on facebook at g.w. africa. earth a home for saving global indios tell stories of creative people and to innovate of projects around the world ideas to protect the climate and boost green energy solutions by global ideas be embodied in series of global 3000 on d w and online. have fun in pyongyang. the capital city of north korea is reinventing itself. but only a few can enjoy the benefits of those the regime allowed. kim jong un introduced an insidious reward system to coerce allegiance to the regime. play those who don't make it into the fun metropolis are often cool and tom green.

have fun in pyongyang starts feb 28th on w. . cut. cut. cut. this is g.w. news why but tonight in the uncertain future here in germany plans for there are after chancellor angela merkel have suddenly fallen apart the woman tipped to take over from chancellor merkel says she is no longer in the running a shocking announcement thoughts on the great prompt insists her decision.