you discover who. subscribed to the documentary on you tube. by roy it's venice shouldn't really exist with its 124 islands and countless bridges and canals this city in northern italy was built in the middle of the marsh . it's proof of human or dangerousness and our ability to muster nature. some advantages there are many beautiful cities in the world but venice is in a class of its own have been into. every year more than

$30000000.00 tourists come to marvel at the palazzo is around the grand canal. these stately townhouses are often takes from masterpieces built using techniques that are unique worldwide. then seems to float away to see over the water but in fact the entire city stands on a forest of wooden tiles 10000000 logs were driven into the much 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. will then this is palaces withstand the danger posed by the water all will they gradually missing. plane.

history of venice began more than one and a half 1000000 years 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 10 kilometers 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 in their sailing ships to find their way around here only the locals knew all the channels so they didn't have to

build walls. even architectural historians like to neteller columbia know very little about the 1st welling's built this area. that has to imagine there are just a few paintings which give us an idea of what things may have looked like on riata island sell the corner of the settlement with that straw thatched wooden huts it was located on reality it was the cost of the only roughly modern if 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 of us. that is beginnings was still centuries away from the venice of palaces and bridges

we know today. the 1st the nice. 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 around it and a church in the middle. with this live look at it that explains why there are so many churches and small squares here because they were the centers of these all the micro towns treat them all. over the centuries the small islands with linked by 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 green consists of sediments 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 are the 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. then this is church tile is 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 pegs. hundreds of thousands of them were driven into the bed of a little. at depths of 3 to 8 meters below the surface architects had discovered in 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 father would lead in order to stabilize the building substrate 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 branch in the mud. the poles put up underneath the buildings in the mud. that come in and clear in oxygen free environment a certain amount of microbes that would normally take a would can get into that. the wood undergoes a process of mineralization it turns rock hard and remains intact for centuries. the most famous the mission buildings were constructed on this building ground of

mud and wood. st mark's square with its balance how it stands 110-0000 foot in piles. the foundations of the realtor bridge rest 112000 pounds. and more than $1000000.00 wooden piles were driven into the lagoon for the impressive lesson to tip a cynic which is built of marble. there are between 8 and 10 i wouldn't piles risk where metre this was the entire city stands on an incredible number of the. it's rather like the opposite of a forest. here the tropics 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. predominant over and large chunks from the surrounding regions were shipped to the lagoon to create extremely expensive building ground. to cope with 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 as 400 plots stand on these unique foundations. from the 11 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 some for. 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 history on the age we are seeing it formed the 1st line of defense against the salt forces. 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 rise and fall of the seaboard. the heights 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. look at reason the palaces on the stone base were designed with the maximum of 3 fuel. they understood when they were building that they couldn't make it to have a because they knew that it was all relatively friends mud into logical talons that still compacts and cause the subsidence. slender columns and large windows in the efforts to build with minimum wage the architects created the special venetian style and again 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. less sure. a long time was probably the most important construction material because of its adaptability and 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. trying to remain flexible in the future to me bhavna division down with bill. that also applied to the flooring between the stories. they used wood which is also flexible

material. another trick and should flexibility with the wall and the floor joining . the beams were set in the walls in such a way that they could always move within them. flexible and subtle venetian buildings like living organisms which adapt their form to the vagaries of the moving substrate. today the traces of this constant death 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 something stocks have become distorted and tilt slightly but not one of the venetian palaces has ever collapsed. given that.

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 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 fell out . there is a well. well in the courtyard of every plant sing by developing a sophisticated system for collecting rainwater then this 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. after seething through the sand 15 water then rose again in a well shocked. 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 all these wells were still in operation in venice until the early 20th century. through the military. 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 fleet of ships built in the new green shipyards venice dominated commerce in the mediterranean region.

the city built on water was totally in its element like a fish and water. divinations had created an architectural jewel in the north italian 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 title water 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 mounts in the course of industrialization a 1000 wells was sunk in order to access the groundwater beneath the bed of the libyan. in the 1950 s. up to 40000 cubic meters of water removed every day. civil engineer pierre tretiak teenie describes the consequences for venice these generate a. decrease of the pressure. and when the pressure of the crease in the bay easing in so the mentor amazing as the basin is these producer compaction must decide the winds and whirling of the land surface that

right now we call it subsidence land subsidence. as a result of this land subsidence venice subsided by 14 centimeters in the early 30 years. after a disastrous flood in $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 they'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. 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 not major floods that

are causing the greatest damage to the city but tried to change. the look we're looking at the water comes and goes incessantly. with each me time 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 and. the water is always against the break and the bricks are very hot and. leaving behind this so which crystallise and as salts crystallize they expand in the body and 12 times and that is a very kind of slow way you can say exploding brick what.

the sun towards here is also attacking the line most have between the bricks loosening them and weakening the entire building structure. to provide more stability more and more steel barry is hoping the wrecked it in the city's canals. today one in 3 venetian finance is damaged and to meet 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 it by the constant boat traffic is very bad for the masonry. the boat's propellers churn up the water which the dish. no only the roads the walls. you know i once the masonry has been weakened. the water also impacts the foundations on the ground. and all that is in the quotes are always travelling past the building.

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 between the piles the centuries old foundations on which the building stands in the attempt to limit the damage the city is introduced to speed limits for water taxis. to launch cruise ships which head for the diggin every day are a further problem. these big ships move huge volumes aborter you know that's our communities principle there's still a body of movement in the body of this ship that gets moved and when they're in there are 2 dead and. all the world narrow

a little bit about the local level rises and then goes down again with the passage of the ship it's a wash of water that moves within you know over tens of seconds or minutes and that's very detrimental to the building foundation. subsidence of the bed the rise of the water level and the waves created by votes and ships i mean that then is fresh and from all sides. the only way to save the cities valuable buildings is to drain the canal basic restoration work but that must be done with great care and. the chook a lot of 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 more say 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 some need it 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 floor is in venice on inhabitable. 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 standard give us venice is destined to go under that is not my prediction but that of people who deal professionally with marine and climate issues you know the prediction has been down in the air and often essentially the same. way the rise my thoughts and between 20405060 something into. the demise of venice no longer seems to be merely a pessimistic scenario. and so once again the engineering of 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 little in inlets and hid in them all trying floodgates at high walls if 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. and most here say 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. 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 as full. on our own ass zuko are shaped who do with or don't you know me and we inject the water into a deep obviously. in arkansas system that it isn't ok to be through the 6 on 3rd and 1000 songs need to be told the day like one walked on. 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. 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 then

sink but the same amount but the plan is not without risks and you cannot do it. in a short time we don't want to can generate any any structure. and for this reason we have to do to inject the safety rate. raising the bet if 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. would prove possible to save the masterpieces of the 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.

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is d w news live from her lead a threat from hong kong authorities to students in a university standoff surrender is the only option. all this after dozens of students staged a daring escape from that besieged polytechnic university 100 though remain barricaded inside beijing says it could intervene to end the standoff.