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. . by roy its venice shouldn't really exist with its 124 imams and countless bridges and canals this city in northern italy was built in the middle of a march. it's proof of human or dangerousness and our ability to muster nature. from a function that there are many beautiful cities in the world but venice is in a class of its own. every year more than

$30000000.00 tourists come to marvel at the palazzo is around the grand canal. these stately townhouses are architectural masterpieces built using techniques that are unique worldwide. then seems to float 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 threats even today. then this is palaces which stand to danger posed by the war all will they gradually sing.

history of venice began more than one and a half millennia ago in a large stretch of course in the northern mediterranean on the adriatic coast of italy. then 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 being only the locals knew all the channels so they

didn't have to build walls or. even architectural historians like to not tell a collab you know very little about the 1st welling's built this area. there's a mash and you know 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 weapon of any of the 1st buildings in ancient venice were built on the most stable areas of the namely out o. comes from alto which indicates a high location by the river with the name of the district also dura includes the word for solid the early city was built at sites like the 3 that. there is beginnings was still centuries away from the venice of palaces and bridges

we know today. the 1st one. and slipped on small islands separated by wolves and. each island had a small village with a similar structure essential an open space with houses a ground it and a church in the middle. with the sleeves look at that explains why there are so many churches and small squares here because they were the center of these all to micro towns and tree. over the centuries the small islands willing to buy bridges which were often built over the water at strange angles. in the 2nd century building space gradually became scarce. the problem could only be solved by developing new manmade areas but

that was far from easy the bed of the digging consists of sediment and much crisscrossed by numerous was of courses building ground that was in constant movement. in one of the real 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 substrates. venice's church tallis mean 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 bed of the lagoon. at depths of 3 to 8 meters below the surface architects have discovered a layer of sedimentary clay known as kind i'm told 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 of the bollywood leader in order to stabilize the building substrate wouldn't piles were driven into the bed in each area. if 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 brought in the mud . and. the poles underneath the buildings in the mud. that come in and clear in oxygen spring environment a certain amount of microbes that would normally take 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 commission buildings were constructed on this building ground of

mud and wood. st mark's square with its balance how it stands 110-0000 foot and pilots. the temptations of the real ship bridge rest 112000 pounds. i'm more than 1000000 wouldn't piles were driven into the lagoon for the impressive last salute of us silica which is built of marble. there are between 8 and 10 i wouldn't piles of pursuit where metre about this with entire city stands on an incredible number of them. it's rather like the opposite of a forest. here the troubles are function like roots it's. all in all an estimated 10000000 wouldn't piles have been driven into the liquor

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. all of venice 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 samples of. 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 built a surround of white stone from istria on the a.g.r. sick it formed the 1st line of defense against the salt force. that deals with the interface between the water and that resist an infinitely long time because it's not probable to the salty water. the resistant strain stone is unaffected by the rise and fall of the sea will set. the heights of this protective wall corresponded to the tidal range and this way

the voice it was prevented from coming into contact with the more sensitive load bearing. the good reason the palaces on the stone base were designed with a maximum of 3 floors. they understood when they were building that they couldn't make it to have it because they knew that it was all relatively friends mud into you know they could tell us that still compacts and cause the subsidence. slender columns and large windows in the efforts to build with minimum waves the architects created the special venetian style eloquent and graceful. but despite the lightweight construction method by no means had all the challenges been overcome.

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 law and mortar. it was used in the construction of the brick walls applied as a cement substitute it has the advantage of remaining flexible. national center. for a long time was probably the most important construction material because of its adaptability 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 me with the vision with them. that will subside to the flooring between the stories. they used to put which is also flexible material. another

trick and should flexibility with the wall and the floor join. with 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 adept taishan are visible in many places in the form of to stores had for some months here and there cracks appear inside the buildings as well. although there have been a couple of instances of subsidence some thoughts have become distorted and tilt slightly cleaner but not one of the venetian palaces has ever collapsed the grolier

. this is architects constructed the buildings 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 for you only in the 1970 something unfair list 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 didn't sell out. there is a well. in the courtyard of every plant city. by developing a sophisticated system for collecting rainwater venice is brilliant architects solve 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. 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 to all these wells were still in operation in venice until the early 20th century with you know all the needs of them of which are. 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 this is he was in its heyday thanks to its powerful fleets of ships built in the lagoons shipyards venice dominated comus in the mediterranean region. the

city built on water was totally in its element like a fish in water. the venetians had created an architectural jewel in the north italians are good. but nature was to turn on them in a dramatic way. as a result of human interference in the clean 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 title was the levels. the natural balance in the lagoon 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 marks in the course of industrialization a 1000 wells was sunk in order to access the groundwater beneath the better for the future. in the 1950s up to 40000 cubic meters of water were removed every day. civil engineer peter t. a teeny describes the consequences for venice these generate. the cream of the pressure. and when the pressure of the trees in a big city mentoring mazing the basin is these producer compaction off the sidelines and

a lot of the land surface right now we call it subsidence land subsidence. as a result of this land subsidence venice subsided by 14 centimeters in nearly 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 i've 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 of zone abuse both 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 . some of the 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 and can no longer protect the palaces from the world. the water is always against the brake and the brake very hard and. leaving behind the souls which crystallise and as salts crystallize they expanded the body and 12 times i'm not like it's a very kind of slow way you can say exploding brick.

the sun to water is also attacking the line moves have between the bricks loosening them and weakening the entire building structure. to provide more stability more and more steel barry is a being a wrecked it in the city's canals. today one in 3 venetian finance sos is damaged and in need of renovation and that is not only the result of the daily tide change motorboats 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 as. far as i once the masonry has been weakened. the water also impacts the foundations on the ground. it all didn't you know boats are always

travelling past the building. it's the number of boats and the frequency of boat traffic that is threatening the walls. the churned up water gets into any cracks in the brickwork and thracians the entire building structure it also uses 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 moves huge volumes aborter you know that's our communities principle there's still a body and we've been at the bottom of this ship that it's new and when they. have to do that they've. all been through a narrow little came out the local level rises and then goes down again with the

passage to be it's a wash of water that moves within you know over tens of seconds or 0 minutes and that's very detrimental to the building foundation. subsidence of the lagoon bed the rise of the water level and the waves created by boats and ships mean that venice is threatened from all sides and. the only way to save the city is valuable buildings is to drain the canals for basic restoration work but that must be done with great care. the cuticle a lot of the work only takes place and drains sections with a maximum length of the 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. and. today more modern methods are also being applied in order to stabilize the walls chemicals are introduced into the nih more time. they prevent borsa getting into the bricks all these measures are carried out by hand. 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 nations. 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. with the stance of previous venice is destined to go under that is not my prediction but that of people who deal professionally with marine and climate issues the prediction has been down from the end of the sun for me to say that the sea level rise my thoughts and we think 20405060 some to me after. the demise of venice no longer seems to be merely a pessimistic scenario. consolo once again the ingenuity of italian i. architects and engineers is called for to save the city. or. the moves

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 him in let's. get in them or try and flood gates at high walls had these can be raised as far as the boston 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 but maybe it's inconsistent i believe to want to protect the city from super floods without at the same time protecting it from decay you know. 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 where. we don't work. on our own ass circular shape we're going to go on with or don't you know meters and we inject the water into it quite obviously we select an option for system that if he's located between 6 on 3rd and 1000 meter below the moon walk. raising such a huge area with an entire city on it is an ambitious enterprise which no one has ever attempted before. the plan is to pump 50 liters of salt water per 2nd. in the wells and into the substance 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 then

sink by the same amount but the plan is not without risks you cannot do works in a short time we don't want people to generate any any structural. and for this reason the us could do to inject at the same stuff 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 monster pieces of the nation architecture from the consequences of human made problems. no one wants to see this city go under bennet's needs visionaries like those who built it people who will think the impossible in order to achieve something magnificent.

place. they were systematically robbed by the nazis. and after the war there were no signs of compensation. for collectors of agata an ounce of gold mine. today researchers are searching for the missing works of art the painful process for the descendants looted art. in 15 minutes on d w. what

secrets lie behind the walls. discover new adventures in 360 degree. and explore fascinating world heritage sites. p.w. world heritage 360 get kidnapped now. have fun in pyongyang. the capital city of north korea is reinventing itself. but only a few can enjoy the benefits for those the shallow. kim jong un has introduced an insidious reward system to coerce allegiance to the regime. those who don't make it into the fun metropolis are often full and tunbridge. have fun in pyongyang starts february 28th on w. this

is d w news live from berlin and uncertain political future here in germany as plans for the euro after chancellor merkel fall apart the woman tipped to take over from the now says she does not want the job a shock announcement what does on a good. decision mean for the government and for the country's future also coming up. on kong's pro-democracy protesters find a way to connect in the crisis they're distributing.