Taj Mahal: Engineering and Construction Secrets of the Mughal Masterpiece

[00:00:00]Documentary In the north of India, in the city of Agra,  stands the Taj Mahal, a monumental mausoleum   of white marble built almost 400 years ago on the  banks of the sacred Yamuna River. I don't think a   building like this will ever be created again. The  dome of this mythical building towers 73 meters,   marking the heart of a vast architectural complex  stretching 177,000 square meters. It's absolutely   grand in scale. So the Taj can really be seen  from the moon or from two centimeters away,   and it's perfect. The Taj Mahal is a symbol  of perfection. The Mughal emperor Shah Jahan   ordered it built in the 17th century as a monument  of love, in memory of his wife Mumtaz Mahal. Today   it is one of the ten most visited monuments in  the world with nearly 7 million visitors each   year. The extraordinary mausoleum took builders  just 18 years to complete and is considered one   of the seven wonders of the modern world. It  is a masterpiece of architecture and I think   it was built as a masterpiece. But it's also  one of the most mysterious with many secrets   still to be revealed. What most people don't  realize is that it is not a building built   in marble. By scanning the mausoleum from  the satellite scale to the molecular scale,   engineers can explore this monumental structure as  never before. We can reach magnification levels of   15,000 to 50,000. The enormity of scale from  the micro to the macro, from the minuscule to   the urban, is really something that makes the Taj  absolutely unique. New aerial imagery exposes the   genius of the architects and the secrets of its  incredible layout. The Taj Mahal looks perfect,   but in fact it's imperfect, a little bit like  the Parthenon in Athens. It gives visitors   the impression of perfection when it's not. How  did builders complete this colossal construction   in under 20 years, when it took creators of  the Notre Dame Cathedral more than a century?   People do not realize that such a complex piece  of construction can be executed in a short time.   What construction techniques, invisible to the  naked eye, are hidden deep within the structure?   I have the mortar sample that I'll insert into the  scanning electron microscope in order to identify   the minerals that are present in the mortar. How  did builders manage to construct a monument of   this magnitude on the unstable banks of a river,  even though the mausoleum alone weighs 25,000   tons. The building managed to survive all kinds  of floods, earthquakes, and heavy rains. History,   science, engineering, exposed as never before,  the Taj Mahal finally reveals reveals itself   on every scale. The Taj Mahal was built nearly  400 years ago at the heart of the city of Agra,   the former capital of the Mughal Empire.  The marble mausoleum is octagonal in shape,   stretching 58 meters on each side and soaring  73 meters tall, sitting on a base almost 100   meters long. Taj Mahal, in many ways, is  hyperreal. While we are in this reality,   we are experiencing something that is completely  out of this world. I don't think a building like   this will ever be created again. Today, the  Taj Mahal is listed as a World Heritage Site.   It is a masterpiece of architecture, and I  think it was built as a masterpiece. I love this   building because it transports me into a different  realm and again to realize that such a complex   piece of construction can be executed in a short  time. How did builders complete the construction   of one of the greatest architectural complexes in  the Indian world in just 18 years? When visitors   discover the Taj Mahal, they're impressed by  the grandeur of the monument and its richness,   with all the materials that are used in its  construction, the marble in particular. But   that's actually just a shell, an envelope. What  most people don't realize about the Taj Mahal is   that it is not a building built in marble. Clues  to expose the secrets of its rapid construction   can be found in New Delhi, 200 kilometers  north of Agra, at another mausoleum,   the Tomb of Rahim. Many archaeologists consider  this monument to be the little brother of the   Taj Mahal. It was built 50 years earlier.  Over time, the monument has been plundered,   stripped of its most precious materials. It  offers scientists a unique opportunity to   explore construction techniques that builders of  the Taj Mahal also used. Examining the structure   at a macroscopic scale shows the original  marble casing conceals other materials. It   does help understanding how the Taj Mahal is  built because the white marble blocks, huge   blocks of white marble that make the dome of Taj  Mahal is built, because the white marble blocks,   huge blocks of white marble that make the dome  of Taj Mahal are really resting on brick masonry   and stone masonry below. A 3D reconstruction  reveals how the dome of the Taj Mahal was built.   Historically, this is how the Taj Mahal  and all of these monuments were built,   where imported expensive stone such as marble  and red sandstone was only the top 8 to 10   inches. And the interior was built of local stone,  random rubble masonry. So how did this building   technique speed up construction? The speed of the  construction of the Taj Mahal can be explained   by the materials utilized by the many builders  who worked on this site. About 20,000 workers,   according to the chronicles of the time.  Scientists think that the use of brick as   a framework offered builders a major advantage.  Brick is also a material that's made locally,   so you have complete control over it right  from its conception, as opposed to sandstone,   where you might have to quarry a lot before  you get the perfect bits. And most importantly,   brick can be manufactured a lot more locally than  sandstone or marble, which has to be brought in   from a large distance away. or marble, which has  to be brought in from a large distance away. Brick   manufacture doesn't require complex logistics.  Today, very close to the Taj Mahal, the principles   of production are almost identical. The clay,  design techniques, and firing are all similar   to those used by 17th century builders. First,  we dig the earth. then we add salt and water.   To make the bricks we put sand in the  mold, then we put clay in the mold,   and then the brick starts to come out. The bricks  are dried in the sun, before being stacked in a   circular kiln dug into the ground, an oven that  runs nonstop. It's filled up in sequence. Every   day, 40,000 bricks are put into the kiln. 40,000  bricks are fired, and 40,000 bricks are taken out.   While workers stack new bricks, others remove the  fired bricks so that production never stops. Look   at the technique. The spacing is made so that  when the coal is put in, it reaches directly   to the ground below. The heat rises and bakes  all the bricks. A 3D reconstruction exposes how   the brick factory functions. It's a perpetual  circle, which allows workers to fire thousands   of bricks continuously. The central chimney  evacuates fumes from the base, accelerating and   regulating the process of cooking. This is a vent  for the chimney. It's closed now. It's a tunnel to   the chimney. There are a total of 20 tunnels in  a circle here. All of them lead to the chimney.   The bricks will be fired for almost a week, with a  peak temperature reaching almost 1,000 degrees. A   factory of this size produces 1.2 million bricks  per month. Bricks were thinner at the time of   the emperor Shah Jahan. Factories were created  on site according to need. Using clay from the   banks of the Yamuna River, the proximity and ease  of production helps explain the speed of building   at the Taj Mahal. Constructing in brick allows  you to build much bigger buildings than if you   did just with stone. It allows you greater control  over the shape of the building. By using bricks,   builders could create taller structures  rapidly. Thanks to the latest technology,   scientists can strip the Taj Mahal of  its cladding and expose its true form,   a skeleton made of brick. The Taj Mahal's  dome hides a secret, too. From the outside,   it appears to be a single dome measuring 18  meters in diameter and 73 meters tall. Looking at   the Taj, most people do not realize that the big  central dome is actually a double dome. Building   two domes on top of each other allowed architects  to build faster and more efficiently. The marble   cladding on the outside obscures the true double  structure hidden inside. For the Taj Mahal,   we have two domes that were built. It's an effect  which the architect wanted. So it gives this   impression to the visitor when they enter the Taj  Mahal. An impression of grandeur with the first   big dome and inside, a smaller one. The ceiling  of the interior dome is just 35 meters high,   while the exterior dome towers 38 meters above.  The genius of the architects was to engineer   a light structure made with brick that could be  built quickly, a giant framework hidden by white   marble cladding. To manage all these works is  something phenomenal. It's really an industrial   project in a pre-industrial age. The craftsmanship  is of the highest order. This indeed is a royal   commission and of the richest empire in the world  at that time. The use of bricks for the Taj Mahal   explains the speed of construction. The internal  skeleton can be exposed with the latest technology   by stripping lining to show how far ahead of their  time engineers were and how they made the building   of this monumental structure so efficient.  The Taj Mahal is an architectural masterpiece,   built 400 years ago on the outskirts of the former  capital of the Mughal Empire, Agra, on the banks   of the sacred Yamuna River, a funerary mausoleum  built by the emperor Shah Jahan in memory of his   late wife, Mumtaz Mahal. But why did the emperor  choose to build the mausoleum on this site, on   soft ground that would make the construction more  challenging? Examining the site on the satellite   scale reveals the secret of its location.  MB Rajani is an archaeologist who analyzes   geospatial data. MIMI RAJANI, Geospatial data is  a large umbrella under which satellite imagery,   GIS tools and techniques, GPS. I use satellite  imagery and the associated technologies to study   archaeological landscape. The study of satellite  data alongside field observations reveals that   the Taj Mahal is surrounded by several dozen  structures spread along the Yamuna River. We   use satellite imagery to understand what the  layout is like. And sometimes these layouts   remain as what we call crop mark, which means  in the vegetation patterns. Or sometimes in road   patterns, we see these patterns. So using these,  we could identify all these 50 riverfront gardens,   which form the center of the Shahjani Agra.  These structures are the remains of ancient   pleasure gardens. In the 17th century, the city  of Agra was the capital of the Mughal Empire,   which dominated India. The elites of the empire  built huge gardens along this river. 3D imagery   exposes the extent of these structures at the  time. These riverfront gardens, that was the core   of the Shahjahan's layout of Agra. So all these  were square or rectangular patches of land. It   was for either the royal family or the nobility.  Pleasure gardens in these prime locations were   a mark of power that only the most influential  families could afford. And the gardens of the Taj   Mahal were amongst the most beautiful. Examining  the Taj Mahal and its gardens by satellite reveals   the incredible precision of their positioning.  So Taj Mahal's location was very important   because he laid it out very interestingly.  If you look at the layout of Taj Mahal,   you draw an axis. It goes straight north-south.  None of the other gardens are aligned that way. So   I think that location was very carefully chosen by  Shahjahan. Aligning the monument and its gardens,   according to the cardinal points, ensure the  prominence of the Taj Mahal alongside other   gardens. But why did the architects choose to  build alongside a meandering river, limiting the   view of the mausoleum? To solve this mystery, we  must examine the monument from the river. We are   fairly sure that the Taj would have been enjoyed  from the riverside and also from within the river,   from boats. So if you're coming from north and  you're coming down this very interesting loop, Taj   Mahal reveals itself. You know, it's almost like  a secret coming. So I think that was also a very   well-planned location to show the magnificence,  even if you are approaching by boat. The Taj Mahal   is part of a series of gardens reserved for the  elite of the country at the time of Shah Jahan.   One of them in particular intrigues researchers  and is the subject of legend. Analyzing satellite   images exposes an enclosure of the same size  as the Taj Mahal, located directly opposite   on the other side of the river. What intrigues  researchers is that this structure has exactly   the same proportions as the enclosure of the Taj  Mahal. There is a myth that a similar building   was meant to be constructed on the other bank of  the river in black marble. Legend has it that the   emperor planned to build his own mausoleum  in front of the Taj Mahal. But researchers   refute this idea. There is no evidence of this  black Taj. And also there is not much evidence,   I think, in the remains over there that it was  any time planned. With no scientific evidence to   support the existence of a black Taj Mahal,  what is the function of the enclosure? Now,   thanks to geospatial data, archaeologists have  a new interpretation. We know that there is a   garden bang opposite the Taj Mahal. And the Taj  certainly was meant to be enjoyed from across the   river visually. across the river visually. This  is Mehtaab Bagh, which is right on the north side   of Taj. As you can see, Taj is there, and we are  on this side, and we have the river in between.   So it's right on the opposite of Taj. And the  layout of Mehtaab Bagh is a mirror image of   Taj's layout. Archaeologists have found traces  of a platform that might have formed the base   of a pleasure pavilion. So I think it's one of  the best views from here of the Taj Mahal. And   no wonder Shahjahan wanted to experience it for  himself, and he had this Mehtaap Bagh made as a   pavilion to view this beautiful monument from.  Archaeologists think the enclosure opposite the   Taj Mahal was an integral part of the monument's  layout, exposing the vision of the architects.   The recent revelations have allowed a complete  reassessment of the site. But how exactly did   this architectural ensemble appear at the time?  To answer this question, experts study the most   recent aerial images and build their ideas on a  particular theory. At the time of the emperor,   monuments and constructions were based on  symmetry. Even ancillary buildings that you see in   the taj complex are built absolutely symmetrically  the gardens are laid out in symmetrical ways and a   central flowing stream of water becomes the axis  along which this symmetry is divided symmetry is   a very known idea and very prominent in islamic  architecture in general and of course in Mughal   architecture. So you will see most of Taj Mahal  has symmetry everywhere. Examining the Taj Mahal   today exposes an obvious symmetry when seen  from the front. It is placed centrally between   two monuments, a mosque and a pavilion for  guests, identical constructions. But examining   the site on a satellite scale reveals that the  mausoleum itself is placed on one end rather   than centrally. Taj Mahal layout itself is laid  out in a rectangle. And if you draw an axis line,   it is mirror imaging on either side. But what  is important is the central line is north-south,   true north to true south aligned. And  also Taj Mahal is placed at the top end,   north end of the layout. Why is the Taj Mahal not  in the center of this complex when the architects   of the time based everything on balance? Is this  a mistake or an aesthetic choice? New technology,   such as the analysis of satellite images, makes it  possible to reinterpret the layout of the monument   and reveal clues about what the site, obscuring  any remnants of the past. A location where people   continue to live gets built over, gets reused and  redone. But seeing a satellite image, we are able   to see the larger layout. So my work can show what  has been the evolution of how the landscape has   been used from the time it was initially built  till now. So if you look at a satellite image,   the area south of the main entrance of Taj  Mahal also has a pattern, a square pattern,   which is of the same measurement as one of  the sections of Taj Mahal also has a pattern,   a square pattern, which is of the same measurement  as one of the sections of Taj Mahal garden. You   see that wall? I think that's part of the old wall  of the Sarai. This monumental structure, identical   in size to the other enclosures surrounding  the Taj Mahal, could be a caravan Sarai,   a place of welcome for travelers, in the form  of a large courtyard that could house merchants,   pilgrims, and their animals. These buildings,  which can be reconstructed in 3-D, were therefore   an integral part of the Taj Mahal complex  at the time of its construction. Over time,   because this has been lived in, and people have  built over it, sort of, the old structures must   have deteriorated and built over it. The analysis  of the satellite images is corroborated by   observations on the ground, like this gateway in  the heart of the old city of Agra. This gateway   is very typical of Mughal gateways, and what you  have is a height that can allow an elephant with a   rider to pass through. There's a terrace up there.  Can we take a look? OK. This gateway in the heart   of the old city could be directly linked to the  Taj Mahal. This is the Dakhani Darwaza. The name   comes from the direction word for south, and  the Dakhani Darwaza faces south. And it's right   on axis with the Taj Mahal. And so it's very  clear that this would be the first gate that   you would pass through in procession to get to  the Taj Mahal. And this is the first of the many   spaces you encounter as you come to the actual  marble monument itself. The architectural complex   that surrounds the mausoleum was much larger than  today. New technology has allowed investigators to   re-evaluate the positioning of the Taj Mahal.  has allowed investigators to reevaluate the   positioning of the Taj Mahal. If the complex is  enlarged by an enclosure to the south, it makes   experts reconsider what lies to the north, the  gardens known as the mettebag and the sacred   Yamuna River itself. So when we see satellite  image of this area, we can clearly see the   Taj complex itself, where the monument is in the  center and the mosque and the Mahmoud Khan on the   other side, the garden laid out in the square with  its axial paths, and on the south of it is the   layout of the entrance complex. By using satellite  imagery, we see that the symmetry is there in   larger scale and larger layout as well. This  re-evaluation of the site gives the sacred Yamuna   River a major role as a natural feature in which  the mausoleum is reflected, a stroke of genius   from the architects of the Taj Mahal. And so one  must not limit the Taj Mahal to being a site that   is only on this bank of the river. But think of it  again as a much larger urban area in which this is   the centerpiece, but the rest of the gardens on  both banks of the river are to be considered part   of the same Taj Mahal complex. The whole site is  not complete unless we appreciate what the site   stands for and not just a single building on a  pedestal. Thanks to new investigation techniques,   researchers can determine that the architectural  complex of the Taj Mahal was nearly three times   larger than today, exposing the talents of  builders who place this mausoleum in the center   of a monumental architectural complex of 475,000  square meters, the equivalent of 66 soccer fields.   In the heart of India rises the Taj Mahal,  a monumental mausoleum whose dome soars 73   meters high, overlooking the sacred Yamuna  River. How could a monument of this size be   built on the shifting banks of one of the  largest rivers in India? Building the Taj   Mahal was incredibly difficult because  of the terrain in which it is located.   The builders had two major challenges to take into  account when constructing the Taj Mahal. The first   was the weight of the building. Since the ground  supporting it There are two major challenges   to take into account when constructing the Taj  Mahal. The first was the weight of the building,   since the ground supporting it had to withstand  about 25 tons of pressure per square meter,   which is enormous. Then its location next to  the Amuna river, which is known to have strong   sedimentation resulting in extensive erosion.  Scientists have analyzed the subsoil of the Taj   Mahal and discovered a mixture of clay and silty  deposits, extremely loose particles unsuitable   for supporting a 25,000-ton monument. You cannot  build a building like this on soft soil unless   you have very firm foundations. You have to  create some kind of solid base. So how is the   monumental structure of the Taj Mahal supported?  The foundations are inaccessible to investigators,   buried several meters deep under the building.  But clues can be found by examining soils by   georadar and analyzing materials with a  scanning electron microscope. Scientists   want to understand how builders manage to  construct the monument at this site. We   want to obtain accurate maps of what we would be  likely to find during archaeological excavations,   but without having to dig. The geophysical  investigations allow us to see elements at depth   and produce a detailed map of the subsoil.  Scientists have used GEO-Radar to discover a   layer of hard soil, located at about 19 meters in  depth. A sandstone layer several meters thick on   which the foundations of the mausoleum rest. But  how did the Mughal architects create foundations   strong enough to support a 25,000 ton structure?  To understand, investigators examine the banks   of the Yamuna River a few kilometers south of  the site. Pushkar Sahoni is a specialist in   Indo-Islamic architecture. What appear to be wells  are actually the piles that hold up this retaining   wall against the massive river of the Yamuna. And  piles like this were made inside the riverbed.   Here is an example of this kind of pile. What you  have here, I'm standing in the center of a masonry   well that is completely filled in with rubble and  mortar. And this creates a pile inside the sandy   banks of the river. And so it can support a big  weight, not just of me, but a million of me, which   would maybe make up the weight of the Taj Mahal.  3D reconstructions exposed the principle of the   foundation well. Engineers designed brick wells,  stretching all the way to the harder ground below.   They dug directly into the clay soils, searching  for the hard ground to create a footing. Then they   inserted a vertical wooden piling and filled in  around it with material. Stonemasons used mortar   to waterproof the tanks. But how did they produce  a waterproof mortar when artificial cement would   not be invented until two centuries later?  The lime used in traditional mortars of the   time wasn't enough to make it waterproof. The  mortar used for the construction of the Taj   Mahal is a lime mortar. But for the construction  of the wells, they used a mortar that allowed a   better resistance to water and erosion. They added  elements that made the mortar impermeable. So what   is the secret of this water-resistant mortar?  Now studying the mortar at a microscopic scale   exposes clues. So here I have the mortar sample,  in powder form, that I will insert into the   scanning electron microscope in order to identify  all the minerals that are present in the mortar.   The electron microscope bombards the material  that will be studied with electrons. First,   the mortar is placed in a vacuum chamber. It's  like going on a spacewalk. Astronauts can't be   sent directly into space. They have to go through  a decompression chamber. As the electrons transmit   through the sample, a very high resolution image  of the material surface structure is revealed. So   here we start to see the mortar and the minerals  it's made of. We can achieve a magnification of   between 10,000 and 50,000, compared to optical  microscopes, which reach a magnification of just   1,500. The microscopic study reveals that this  mortar is not only made of minerals. We can see   that the mortar is also made up of small grains,  whose appearance is reminiscent of the morphology   of plants. And probably it's actually seeds. It's  quite surprising to find plant debris in mortar.   Several types of plants have been identified. I  also isolated black particles. It's hard to tell   if they are mineral or plant species. But they  could be spices, like pepper, for example. By   analyzing the composition of the mortar under  the microscope, scientists have discovered the   presence of many natural materials. Sugar, spices,  chickpea flour, a local fruit, and tree resin.   Investigators have shown that the ingredients have  highly impermeable properties. This analysis of   the mortar, coupled with the analysis and mapping  of the geophysical surveys, allows us to establish   a more precise plan of the foundations. A 3D model  exposes the scale of the Taj Mahal's foundations.   Hundreds of shafts support the phenomenal  weight of the monument across nearly 35,000   square meters. So what you have in effect is  something that almost looks like a bed of nails   turned upside down on which the building is built.  Of course, the nails we are talking of are nails   that are large and also very deep. The shafts  are connected to each other by brick arches,   which distribute the weight. A 3D image of  the foundations exposes the talent of the Taj   Mahal's engineers, who built a solid and efficient  structure that would survive the centuries. As we   can see, the building has stood the test of time  completely. It has managed to survive all kinds   of floods, earthquakes, and heavy rains. Today,  however, scientists are alarmed by the Yamuna   River's decreasing water level. Records of drought  and heat taken each year suggest a looming threat   to the structure of the Taj Mahal's foundations.  A key element of each foundation shaft is the wood   that runs through them, wood that survived until  today, because the foundations were submerged by   river water, creating an oxygen-free environment.  The fact that the wood is dry when it has been wet   for hundreds of years will create instabilities  to the supports of the platform and therefore the   monument itself. This will create fragility. So  there's a regular monitoring of these foundation   shafts. Despite the environmental risks, the Taj  Mahal remains one of the most stable monuments   in the Indo-Islamic world thanks to revolutionary  construction techniques. The Taj Mahal represents   an amalgamation of construction techniques  which do not only come from India. They are   also imported from Central Asia, from the Iranian  world. These are notably used in the construction   of military works, forts and also dams. The  foundations of the mausoleum are inspired by   military architecture and civil engineering and  are intended to be indestructible. They represent   the most successful construction techniques of  Asia at the time of the Emperor Shah Jahan. The   Taj Mahal was built by the Emperor Shah Jahan  400 years ago, after the death of his wife.   Today it's a symbol of beauty. Millions of  visitors come every year to admire this icon   of perfection. But what is the secret  to its appearance? This architectural   masterpiece shines because of the marble  that covers the monument. The magic of   the Taj Mahal lies in its changing color.  Gray, blue, pink, white, orange. You have   marble. It has grain that is slightly gray and  black. And it lends itself to very pleasing,   changing surfaces. It interacts with the  atmosphere. It interacts with the weather   and looks different in different kinds of light in  different seasons. This transforming color palette   is due to the specific marble chosen by architects  to cover the Taj Mahal. It's a unique stone.   Examining samples under the microscope reveals  that it's composed of dolomite, a mineral more   resistant than limestone, but with other similar  properties, especially its exceptional capacity   to reflect the light. This marble comes from the  Makrana mines, 400 kilometers from the Taj Mahal.   Examining the area on a satellite scale exposes  deep gashes that pierce the ground surface. At   the foot of the Aravali mountain range, there  are more than 400 quarries that still extract   Makrana marble. The mine is spread over 20  kilometers. Now we have reached 90 meters   deep. It will never run out. There will always  be marble. There have been surveys up to 300   meters deep. There will always be marble. There  have been surveys up to 300 meters deep. This rock   was formed nearly 400 million years ago by a rise  in temperature and pressure deep within the earth.   Impurities in the minerals create its unique  color and its marbling, features which make   Makrana marble unique. This marble came out of the  mine and weighs five tons. It will be brought to   the factory by truck, and then it will be cut.  When the Taj Mahal was built, Makrana marble   from these mines was cut into slabs by stonemasons  before being transported to the building site. The   brilliance of the stone would become the defining  feature of the monument. However, a few years ago,   scientists realized that the marble was losing its  shine and becoming yellow. There was an enormous   problem with deposits of several hundred years  that had accumulated on the marble. And these   had to be removed because they were giving the  Taj Mahal a permanent yellow tinge. So how do   you restore the splendor and shine of marble?  Engineers in charge of cleaning the monument   found a solution that was inspired by ancient  techniques, avoiding the irreversible damage   caused by many modern chemical substances. And  this was done using a variety of treatments,   mostly reversible and natural treatments, such  as using Multani Mitti or Fuehler's Earth as a   poultice on the surfaces, which would absorb  all the contaminants. This cleaning technique   sometimes appears to be more like a beauty  treatment than a maintenance procedure.   The cleaning processes that have been used on the  Taj have involved Multani Mitti, which is used   commonly as a face pack. And the same is happening  with the Taj, where Multani Mitti has been used to   cover the face of this beautiful maiden, and  then it's been removed to make it glow again,   timelessly. The secret of this technique's success  can be revealed by modern science. Examining the   mixture on a molecular scale exposes a bentonite  clay called Multani-Miti. This volcanic clay   is composed of potassium, sodium, calcium, and  aluminum, molecules with the property of absorbing   toxins from the rock to restore its purity. Ground  to a powder and spread on the marble, it becomes   a perfect beauty mask for the iconic Taj Mahal.  Unfortunately, this marble also looks different in   different kinds of pollution. And so a number of  air polluting industries around the area were shut   down in the previous few decades. To mitigate the  risks of pollution, the Indian authorities have   excluded all polluting industries in a 10,400  square kilometer area around the Taj Mahal,   and banned motor vehicles in a four kilometer  square radius around the monument. Today, the Taj   Mahal shines as if it's new, impressing the  millions of visitors who come to marvel at its   perfection each year. impressing the millions of  visitors who come to marvel at its perfection each   year. But does the Taj Mahal really achieve true  perfection? And how can perfection be evaluated?   The monument appears to be perfectly balanced  and symmetrical. It stretches 60 meters on each   side and its dome towers 73 meters high. The Taj  Dome is a central attraction. When you see the   monument, the dome is so huge and so beautiful, it  almost looks like a balloon that is going to lift   the rest of the monument up. To the naked eye,  the dome appears to be perfectly proportioned.   It was a colleague of mine who said the dome is  not a symmetry. I found it very strange to believe   this. So in order to check that, we took the  center of the drum and the center of the finial,   and we drew a central line. And we took  equidistant intervals, and we measured the   right side and measured the left. So here, the  drum is equal, but as you see, one side of the   curve bulges more than the left side of the curve.  So the largest bulge is about 62 centimeters. The   62 centimeter difference between the two curves  of the dome is a notable difference in terms of   construction, even if it's not obvious visually.  It's a three-dimensional object, between the two   curves of the dome is a notable difference  in terms of construction, even if it's not   obvious visually. It's a three-dimensional  object, so it has this onion-shaped exterior,   and the interior is hollow. So it's not easy to  have a plumb line in the center from which you   can measure when you're building. So I don't think  it was an intentional asymmetry. I think it is a   complexity of a three dimension. And there are  other anomalies identified by archaeologists.   Using modern measurement techniques, such  as photogrammetry and laser measurements,   investigators discovered that the Taj Mahal has  symmetry defects in other symbolic areas of the   building such as the minarets. It's been a bit as  you can see that's likely to did out word. I don't   think it is a imperfection or a mistake I think it  that is a deliberate kind of tilt because in case   there was a way and the minute had to fall off  if it was straight it was quite likely it would   fall on the monument and damage the monument. So  I wouldn't call it imperfect, but it is a part of   the design. For some archaeologists, these are not  mistakes, but deliberate decisions by architects,   whether for structural reasons in the case of  the minarets or for geometric reasons to trick   the eye. It's a perspective to give visitors  an impression of geometry and perfection,   even when it's not the case. From the start, we  have a construction with elements deliberately   misdirected to give the viewer that sense of  geometric perfection. Even the imperfections   of the Taj Mahal, whether intentional or not,  serve the splendor of the monument and reveal   the harmony that its architects aimed for. If you  say perfection is by precise measurement, then you   can find flaws. So I think perfection in itself  has both subjective and objective connotations.   So however it is, I think it's a very beautiful  and breathtaking monument, no doubt, whether you   call it perfect or imperfect. The magnificence of  the Taj Mahal goes beyond its incredible symmetry   and gigantic proportions. The walls of the  facade and the interior of the mausoleum   are decorated with thousands of floral patterns.  But how could the monument's builders have created   such intricate and colorful detail in marble, a  particularly hard rock? Analyzing the patterns in   detail reveals that they are formed from stones  inlaid into marble. It's a technique still used   today by the descendants of the craftsmen who  worked on the Taj Mahal 400 years ago. worked   on the Taj Mahal 400 years ago. We're currently  placing the mortar to inlay the gemstones. The   technique is called pietra dura, the inlay of  precious stones. Here, they cut the stones. The   design of the flower is made here. Some of the  colorful gems used in the Taj Mahal aren't found   in India. A recent study by the Gemological  Institute of America has discovered the exact   provenance of each of the stones in the Taj Mahal,  revealing that the stones were sourced from all   over the world. The Taj Mahal was planned as one  of the symbolic monuments of the empire of Shah   Jahan, and that was reinforced by using precious  stones sourced from all over the empire. So there   are garnets that come directly from India, lapis  lazuli from Afghanistan, carnelian from outside   the empire from the Iranian and Iraqi world. Other  stones came from even further away. Emeralds mined   in the Americas arrived by boat. Amber from Europe  was transported over land. Diamonds came from   Africa. Lapis lazuli from Iran. Stones from far  beyond the Mughal Empire. The fact that the Mughal   Empire was an agricultural and also military power  allowed the development of a whole network of   roads throughout the empire. And these roads also  served to supply materials to the great capitals   of this period under Shah Jahan. By choosing  precious stones from all over the planet, builders   wanted to symbolically place the Taj Mahal at  the center of the world. Researchers today are   still impressed by the sheer magnitude of the  detailed stonework carried out at the Taj Mahal.   The use of these different materials, these  precious stones, is exceptional for this period,   because we don't usually find that same richness,  the use of all these precious stones in a single   monument. The inlay of the Taj is exquisite  because while it is something that has to be   done precisely on a small scale, it covers  entire surfaces. And just sourcing these   stones of different colors from various places in  the empire and indeed across the world itself was   an extraordinary feat. The quality of stonework  required exceptional craftsmanship and skill,   another sign that this monumental mausoleum  was as much a show of power for the emperor   Shah Jahan as the creation of a  masterpiece close to perfection.   The emperor and his architects had created one of  the most beautiful monuments in the Mughal Empire,   but their project was even more ambitious. The  designers of the Taj Mahal wanted to reproduce   paradise on Earth. The layout of various  courtyards that led to the mausoleum itself   played a role. The successive spaces, from the  caravanserai to the mausoleum, corresponded to   a spiritual path. This is the courtyard just in  front of the actual innermost enclosure garden of   the Taj Mahal. And so one has to think of the Taj  Mahal as a series of movements. Just like you have   in a musical composition where you might build  up. You go on till you come to the crescendo. And   this is the last place where the building will be  slowly revealed to you. And as you approach this   doorway, you will slowly see parts of it emerge.  And so it's like a teaser. And once you get to   that entrance, suddenly it really comes up upon  you. A symbolic passage from the terrestrial world   to the celestial. Inside the final enclosure,  satellite images upon you. A symbolic passage from   the terrestrial world to the celestial. Inside the  final enclosure, satellite images reveal that the   garden is divided by four water channels. The Holy  Quran repeatedly promises the faithful gardens   beneath which rivers flow as their final resting  space. So paradise is really defined by the four   rivers of paradise, but that is most evident at  the Taj Mahal, where the water flowing represents   the four rivers of paradise. The mausoleum itself  is an octagon, a significant choice. The Holy   Quran talks about the eight gateways of paradise,  and the central tomb chamber at the Taj Mahal is   surrounded by eight chambers, which represent the  Hasht Bheesh, or the eight gateways of paradise.   The dome and the minarets represent the ascent of  souls to heaven. Even the imperfections found here   demonstrate the desire to represent paradise on  earth. They believe that only God can be perfect.   Human beings are not perfect. And very often,  they do induce a small element of imperfection to   keep up to that work. The Taj Mahal is an icon of  beauty. Its stunning symmetry, exquisite detail,   and gleaming finish make this monument unique. I  think the Taj Mahal is an incredible building that   has caught the people's imagination for almost 400  years. New technology has allowed scientists to   carry out a complete reassessment of the Taj Mahal  and its grounds. Studying its foundations reveal   that the builders used techniques from civil and  military engineering in their quest to make the   building as resistant as possible. The Taj Mahal's  location has been re-evaluated using new satellite   images, exposing that the monument was once at the  center of a complex much larger than today. that   the monument was once at the center of a complex  much larger than today. The search for perfection   has been found in all aspects of construction,  from the detail of the floral decoration to   the search for perfect symmetry. Not only is it  absolutely grand in scale, but it is also perfect   in symmetry. So the Taj can really be seen from  the moon or from two centimeters away, and it's   perfect. The latest revelations reinforce the  Taj Mahal's status as a mausoleum with no equal.   Thanks to the latest technology, the Taj Mahal is  exposed as much more than a simple mausoleum built   for love. The ambition to reproduce paradise  on Earth symbolizes the power of Shah Jahan,   and the skill of its construction ensures  the Taj Mahal still shines centuries later.