Angkor Wat (Full Episode) | Access 360 World Heritage

The temple of Angkor Wat is one of hundreds of temples that make up the Angkor World Heritage Site. Angkor was once the largest city on Earth. Then, seemingly overnight, this ancient metropolis of nearly a million souls vanished. Now, experts are using new technology to solve this great mystery and restore the treasures of a lost empire. Damien Evans is one of a new breed. They call themselves aerial archaeologists. He's on a mission to map the ruins of the lost civilization below. What we do is we look at the landscape as a whole. If you're on the ground, you really can't see what's what. You really have to get up in the air and get an overview, a broader perspective on the landscape. New technologies are allowing Damien to trace urban boundaries and landmarks like never before. Lasers mounted on the helicopter can cut through the jungle to detect topographical details hidden beneath. For the first time, Damien is able to map the full reach of this ancient megacity. The maps show the area of Angkor was the size of modern-day Los Angeles. The Angkor was the largest settlement complex that had ever been built in all of human history before the Industrial Revolution. Ancient Angkor was the capital city of the mighty Khmer Empire. For six centuries, this military superpower conquered and controlled a vast kingdom in Southeast Asia. Then, just as Europe was entering the Renaissance, this thriving 3,000-square-kilometer city was swallowed up by the jungle. Damien is searching for patterns below that may indicate how this city functioned and why it suddenly collapsed. The problem here is that you can be standing right in the middle of a city, a 1,000-year-old city, and not even know that you're right on top of it. Once you get up in the air, you're able to map these things. You can see the spatial patterning, the traces of these things in the landscape. His teammate, Scott Hawken, coordinates from the ground. Scott's expertise is in decoding the ruins of ancient cities. Stone structures were built for the gods. So temples are nearly all that remain standing. But new laser technology can detect the traces of structures that disappeared hundreds of years ago. We found hundreds and hundreds of additional temples. We found the remains of canals, even a small road from 1,000 years ago. Even if it's completely overgrown, you can still see the trace of that road. Why this thriving capital disappeared is a total mystery. The inhabitants of Angkor left no written records that indicate an invasion, plague, or other catastrophic event. So what did go wrong here? While Damien and Scott look for answers, other teams in the park are in a more present-day struggle. They're out to save the fragile temples left behind. Glenn Bornasian is a lead architect for the World Monuments Fund. Glenn is directing a massive effort to prevent one of the park's oldest temples from literally crumbling apart. One enemy of this place is water. When water gets behind, it is an exponential process. So it was basically a systematic collapse of the site. Stone shrine. We have the same problem everywhere. We can see that the façade stone has all collapsed because of the erosion over time and the amount of water that came in. And that dirt gets wet and puts pressure on this façade wall. It's caused the collapse. What do you think the next steps are to try to fix it? We start with the stabilized, with the new laterite block at the back, just like the ancestors did before. Right. The temples, then and now, are built by stacking a core of laterite, then encasing it in intricately carved sandstone. These stones are so tightly laid that you can see behind me, you can't stick a piece of paper in between them. Today, if you ask somebody to do this wall, almost impossible. The first step of the restoration is removing the ancient sandstone blocks so the team can install a new laterite foundation. It's a huge undertaking. There are stone coming down. And there's stone going up. This is a very busy place. To the workers that built this temple in 900 A.D., Glenn's modern tools would have seemed like magic. The crane can do in weeks what would have taken thousands of workers decades to build. Using a single crane, Glenn's crew can move up to 15 one-ton blocks of laterite every day. Good, let's keep bringing it down. Now the site is ready for the original sandstone blocks to be put back in place. The crown jewel of the whole site is the 800-year-old Angkor Wat. The temple complex is a literal depiction of Hindu cosmology carved in stone. It took some 300,000 workers about 40 years to build this enormous temple. Certified guide Po Thai Khin believes Angkor Wat and other temples are entering a new age of peril, the age of megatourism. We have buses loaded with tourists coming in each day, from 3,000 to 4,000, 5,000 a day coming into the park. You walk along the gallery of the bas-relief, you see people just touching to that bas-relief, and sometimes a whole tour group is just putting their hands in there. When I see the temple that's being damaged, I just feel sad. Angkor and Angkor Wat, it's part of the soul of Cambodia. It's buried in our heart as the symbol of our people. The surface of this monument, it's part of the history. We could erase the history. The best way to discover why Angkor vanished is to understand how it thrived in the first place. Damien and Scott are looking for structures that reveal how a small jungle village grew into a sprawling urban superpower. Damien, I can see you. I can see the chopper. Yep, you're just nearly there. Scott's on the hunt for specific details that will expose the true story behind these ruins. I'm just walking along the face of the wall now. And it's made of these massive laterite blocks. The blocks are, like, over a meter length, very nicely carved laterite, and butted together very precisely. This is a precision-engineered structure. Scott has just come across a major find. I'm walking down what looks like to be this monumental stair between these great laterite blocks. There's another architectural feature, jutting out at the exact year on the other side. Well, these two massive parallel walls look like they could have been used for some kind of channel. Whether it was used to stop water going in or going out, that's hard to say. These ruins appear to be part of an ancient canal. They've now found a key piece to the puzzle. New aerial imagery has revealed an ingenious network of canals and reservoirs throughout the city. Obviously, the reservoir behind me is easy to see. For the most part, though, we can't see water in them today. But we can look at traces and features of the landscape that tell us that we have this huge water management system here. Even the river in the modern town is actually an ancient canal, still flowing today as it did 1,000 years ago. The centerpiece of the system is an 8-kilometer-long, 2-kilometer-wide reservoir just outside the city. This reservoir alone would have taken 6,000 workers more than six years to dig out by hand. The team wants to know why the ancient Khmer went to such lengths to divert water on such a massive scale. For a long time, there was this idea that they were purely religious structures, just there for the gods and spiritual reflection. But looking at these stone features that are inserted in the walls of the reservoir, you can understand that these are functional, engineered features, and they would have been able to handle vast quantities of water. Understanding how this system functioned will help Damien and Scott reconstruct the rise of the Khmer Empire and perhaps uncover the reasons for its downfall. When the Khmer Empire collapsed, the temples of Angkor were lost to the world for over 400 years. By the time French explorers found it in 1860, the temple had nearly been devoured by the jungle. A special unit of the forestry team is gearing up to defend Angkor Wat from an unexpected threat. Pigeon guano has sprouted seedlings high above, on top of the temple towers. If the tree is allowed to grow, the root will go deeper and deeper into the stones. It will destroy the whole temple. The only way to remove these invaders is to climb. The climbers are nearly 65 meters above the ground. Now the team can get to work. They remove every plant they see and pour a poison to keep the roots from sprouting again. Weeding duty at Angkor is no walk in the park. It's scary at the top because it is so high, but the view is beautiful. This is our little contribution. We are very proud to be able to protect our heritage. Meanwhile, Damien and Scott are trying to uncover the secret of the Khmer Empire's success. A new clue lies in the ruins of an ancient canal. I can see some circular holes and other grooves which could have been these fittings for wooden structures. It looks like there was some other structure integrated into the wall here. What can you see up there? The need to change the flow at different times of year points to only one thing. The climate. Cambodia has only two seasons, wet and dry. The key problem for early civilizations in this area is you have too much water for half the year and not enough water for the other half of the year. So the secret of success of civilizations in this area is their ability to develop technological solutions to that fundamental problem of water supply. The ancient Khmer designed a system that could store excess rain in the wet season and then disperse it in the dry season. The key was digging enormous reservoirs. From the helicopter, it gives us an opportunity to see the reservoir and we can see how that outlet is plugged into a system of distribution. When the spillway was opened, tremendous water pressure from the reservoir forced water down a network of canals and into the rice fields below. This is the reason why the Angkor civilization was extremely successful because their engineering achievements in terms of water management were unparalleled pretty much anywhere else in the world. This engineering feat would be massive even today. What this hydraulic superstructure did was provide stability for the city of Angkor. So if the rains failed, there was this backup system so the farmers could still continue to grow their rice. Some 48,000 square kilometers of fertile rice paddies supported a huge urban population and turned ancient Angkor into a dominant empire. Now the question is, why and how did it all fall apart? Today, all that remains are these ruins of a lost age. Angkor was founded in the 9th century as a representation of Hindu cosmology. Like the ancient Mayans across the globe, the Khmer calendar was based on the cycles of the heavens. Now, twice a year, tourists can witness a celestial event that the Khmer kings used to demonstrate their divine right. It's when the sunlight coming straight over our head and the sun comes straight from the top of the towers and it bring this beam of light down. The alignment of the capstone focuses an intense beam into the ceremonial chamber. You see this light falling from that hole on the top of the towers and then it falls right straight on the top of the pedestal. When it happened twice a year, that's what the Khmer king believed that this is the way that they could reach to the god, to reach to the heaven. The king could communicate with the god. The Khmer king believed that they are devaraja. The devaraja mean the god king. The kings used their divine power to command thousands of servants to build the temples and reservoirs that turned Angkor into an ancient megacity. Khmer Empire's transition to Buddhism in the 13th century was a fundamental shift. For one, the kings were no longer venerated as gods. Building Hindu temples came to a halt. And new evidence suggests they may have stopped maintenance work on their complex water system as well. We know that they have this very delicate water management system and we know that towards the end of the Angkor period the water management system collapsed. The big issue for us has always been why. Archaeologists have discovered a stunning clue hidden in the jungle below. Some colleagues of mine have managed to go up into the highlands cut down one of these ancient trees and look at the tree rings inside that tree. What they can do is reconstruct rainfall on an annual basis going back hundreds and hundreds of years right back to the Angkor period. It shows us these incredible droughts these periods of 20 or 30 years of very, very low rainfall right at the end of the Angkor period. For a water system already in disrepair this mega drought would have been catastrophic. Ironically, the city was doomed by its own ingenuity. Their increasing use of technology and this expanding water system allowed them to move into more marginal areas of the landscape. But this made them dependent on this hydraulic superstructure. When the system failed during the drought Angkor could not grow enough rice to sustain itself and the civilization collapsed. All that remains of this mighty empire are ruins. Today, the pressure on the park to protect these monuments is enormous. But the teams of workers and researchers never rest in their fight to preserve the last legacy of the lost city of Angkor.