Inside the Most Dangerous No Man's Land on Earth | Free Documentary

Korea. Once an ancient mountain kingdom, now a land divided into north and south by conflict. Separated by a no-man's land for 65 years. The DMZ, Demilitarized Zone. Forsaken by the outside world, free from human interference, it's become a pristine wildlife habitat. Unseen, unexplored. This is Korea beyond the border. Seoul. Home to 25 million people. Half the entire population of South Korea. My name is Kim Rae-young. I'm 19 years old. I'm a freerunner. All young men in Seoul must serve in the army. In a few months this teenager will be called up. But for now, he's free. But this is a city under a deadly shadow. Only 35 miles to the north lies the infamous Korean Demilitarized Zone. Young conscripts from Seoul may be sent to guard this notorious line at any time. It is the most heavily guarded border on the planet. The DMZ snakes across Korea like a jagged scar. 150 miles long and two and a half miles wide. Stretching from the Yellow Sea in the west, cutting the peninsula in half. In the 65 years since its creation, both North and South Korea have grown. And their uninhabited areas have shrunk. Leaving the DMZ as the last true wilderness on the peninsula. And home to the greatest variety of species anywhere in Korea. A rat snake. She has just given birth. This tree stump offers some protection, but fundamentally they are on their own. As with most snake species, they will have to teach themselves how to hunt, looking for insects or frogs. It is a dangerous place for a young snake. As hatchlings, they are defenseless, reliant on camouflage. Their forked tongues can detect the scent of prey on the air. But when they are this young, they often become prey themselves. Wild boar. Rat snakes make the perfect snack for these forest giants. There are many species of snake here and boars eat them all. The snake's methods of attack are of little use here. A snake's first day may also be its last. It is thought there are more wild boar here than anywhere else in the Koreas. And the population continues to grow. The infant survival rate here appears to be exceptionally high. With every generation, their numbers increase. The females live in groups, whereas males are usually solitary. But the breeding season brings them together. They course with testosterone. Their testicles grow to twice their normal size. Their jaws expand and they develop a thick fibrous armor beneath their skin, especially in the shoulder region. Ready for a fight. Fights can be vicious. By the end of the rut, they can have lost up to 20% of their body weight. But it's worth it for the victors. The territory and the females are theirs for the season, if they can catch them. It's not clear whether the boars descended from a population that or migrated into the DMZ from North Korea. Very little is known about the fences there, or when they were erected. The northern side of the DMZ remains a mystery. It is this mystery that sustains a high level of tension at the demilitarized zone, even after all these years. But that tension is easy to understand when you consider what happened here. And why the DMZ was created in the first place. In 1950, Cold War tensions plunged the Korean Peninsula into war. One of the fiercest conflicts of the 20th century. More bombs were dropped on Korea than on the entire Pacific region during World War II. The war finally concluded with a ceasefire and the creation of the demilitarized zone. That was 65 years ago. It has left a scar on Korea that is felt throughout the peninsula. This Buddhist monk lives in the forests just five miles from the demilitarized zone. He has lived here for many years, seeking lessons of tolerance and coexistence, and has dedicated much of his life to observing wildlife. But no level of protection can avoid all. Deep in the forest, wild eastern honeybees, workers collecting pollen. They are the chief pollinators in the forest, and they belong to an enormous colony of 30,000 bees. This hollow tree has provided shelter for bees for many years. Inside is the heart of their community, complex and cooperative society. All completely dedicated to the colonies. Sometimes the workers vibrate to create the perfect temperature for these, their precious larvae, the next generation. Thousands of bees working in perfect harmony until there is a threat from the outside. A giant hornet, five times bigger than any bee, able to kill with a single bite. But this hornet is not here to attack, but to seek information. Information he can take back to his own colony. This small gang of predators have taken over an abandoned burrow on the other side of the forest. Using an advanced form of chemical communication, the scout passes on details of the exact location of the honeybee's nest, and leads them back to the hive. Bee colony is an important source of food for the hornets. Bees shake in unison to warn off the enemy. But the hornets don't stop. They hunt for ways to break into the hive. Just a few hornets can exterminate an entire colony of bees in a few hours. First, they tackle the guard bees. They are after the protein-rich larvae inside. Individual bees have no chance against the hornets. And the hornets are too heavily armored for any bee sting to be effective. The bees are picked off one by one. The colony is almost defeated. But it's not over yet. The bees have not given up. Handful of guards start a counterattack. It appears suicidal. But the bees are programmed to lay down their own lives for the survival of the colony. The fight back has begun. The bees' stings can't kill the hornets. As their attackers retreat, the bees unleash their secret weapon on the last remaining enemy. They work together, paralyzing the hornet. Creating a ball. And then, the bees vibrate. Raising the temperature at the center to a level the hornet cannot withstand. Cooking it alive. The bees have developed this unique defense over millennia. Millennia which have seen this battle fought again and again. Since the DMZ was created in 1953, fences have been erected from coast to coast. Cutting it off from the outside world. Impassable barriers to all but the smallest land animals. But no barrier to those who can fly over them. Among the first birds to return were those which hold a special significance in Korea. Cranes. A symbol of peace. These are red-crowned cranes. One of the rarest birds in the world. There are thought to be just 3,000 left in the wild. These cranes spend most of the year in Russia. But in winter, they migrate 500 miles south in search of warm climes to feed. And in the DMZ, they found a perfect environment. Before the war, cranes had visited these areas for hundreds of years. Their homecoming was recorded in 1961. And some have returned every year since. When they first arrive, the sudden proximity of so many cranes can lead to tension. With a wingspan of two and a half meters, everyone needs their space. These stopovers allow males and females to become reacquainted. And they do it in the most beautiful way. They dance. Cranes' return, so soon after the war, marked the beginning of a dramatic transformation of the land between the fences. By the end of the war, large areas of the DMZ had been destroyed by bombs and fire. But even in areas scorched bare by napalm, life can always find a way through. And it is often the lower forms of life that prove to be the hardiest, adapting to the new landscape. The basic ingredients of life can never be totally eliminated. As the land was left to vegetate naturally, regeneration occurred. The DMZ is a long and narrow strip of land, running east to west across the peninsula. From mountains to forests, wetlands to rivers, it contains the biggest diversity of habitats seen anywhere in Korea. The endangered Amur Goral have sought refuge in the mountains in the east. It may be close to extinction elsewhere in Korea, but here it is thriving and moves freely between the mountain wilderness in the center and the apparatus of war at the edge of the DMZ. There are some species that flourish deep within the protection of the DMZ. Mandarin ducklings, a very rare sight in Korea. These ducklings, at less than 24 hours old, are ready to fly their nest for the very first time. So they are a little nervous. It's a six meter drop to the forest floor, and with these tiny wings, that's a long way down. So it's just as well they can bounce. Their spongy feathers and flexible cartilage skeleton cushion the fall. Eventually, they all make it to the water to join their mother. Although many of Korea's best preserved natural habitats exist within the DMZ, the war itself created some wildlife niches. Deep trenches were excavated to protect troops during the conflict. Many bomb craters can be found throughout the same area. Here is a perfect home for fiddler crabs, a cooperative leaf-eating colony who are experiencing an unrestricted growth. But this growth is not one-sided. The ravenous crabs give back to the swamp. These ecological engineers recycle the leaf litter through their digestion, feeding the system with valuable nutrients. While their burrows oxygenate the soil. It may have been reclaimed by wildlife, and many of the scars of war are now grown over and forgotten. But there are still some remnants of the conflict that remain a serious threat in and around the DMZ. There are thought to be one million live mines strewn throughout the DMZ. People still die here stepping on landmines. In certain areas, the soldiers carry metal detectors. But the vegetation is thick. They must tread carefully and follow each other's footsteps. Mines remain the number one killer. These landmines, although extremely dangerous for humans, explain why this is such a pristine wildlife habitat. This is the most natural habitat in the DMZ. A perfect nesting site for one of the world's most endangered birds. The black-faced spoolbill. Its characteristic bill is almost half a meter long. It's an excellent tool for fishing and a powerful weapon. After the war, the island lay barren for many years. At that time, there were only 300 of these rare birds left in the world. Today, the global population has recovered, and there are about 50 spoolbills on this island alone. The recovery has been so strong here. The competition for space is fierce, especially during the breeding season. Spoolbills do not mate for life, but they are strictly monogamous at this time of year. After mating, the male and female stay together for the rest of the season to rear their chicks. So the females are understandably picky. The male must impress. A strong, well-formed bill is essential. He strokes her, reassuring her that he is no threat, and his interest is purely romantic. Male spoolbills are dedicated fathers. So once mating is over, they immediately set about finding the necessary materials to build a nest. The nest is made up of two components. A solid structure built with thick branches and smaller kindling that helps insulate the eggs and block out the wind. Everyone is after the best materials. Many of the spoolbills have been nesting here for some time. The island is filled with precious clutches. At various stages of development. But if they were looking for a stress-free environment, this island may not be the answer. The spoolbills have some annoying neighbors. Black-tailed gulls. A common sight in ports and beaches around the Korean peninsula. And a bit of a pest, put it mildly. The spoolbills may have the edge on size. But the gulls make their presence felt in other ways. This is an important nesting site for the gulls too. And they refuse to be squeezed out by the growing spoolbill population. There is only so much grief a tired mother can take. Everyone has a breaking point. The gull has got off lightly. That giant bill could have done some serious damage. In three months, these hatchlings will fly south with their parents for the winter. There's a lot of work to be done to get them ready for the long journey ahead. The DMZ attracts wildlife from across the globe. In the autumn, chum salmon travel thousands of miles across the North Pacific to spawn in the rivers of their birth. When they reach fresh water, the males jaws and teeth adapt. Ready for the vicious competition that lies ahead. They fight for access to females. This is the only opportunity to breed they will have in their entire lives. So the fight is bitter. Once over, mating can begin. The red stripes on their sides indicate they are ready to mate. The female lays her eggs, up to 7,000 of them, in shallow craters. The male fertilizes them and then they go their separate ways. The adults have fulfilled their purpose. They now stop and let nature take its course. Below the forest canopy, micro dramas of life and death play out. The rhinoceros beetle is on the hunt. His time is short. They live most of their lives underground as larvae. When they emerge in their armored adult form, they have just four months to live. And one thought in mind, find a mate. He uses his keen sense of smell to search for a sap leak amongst the branches. It's a favorite food among females. But he's not alone. Other males have the same idea. The rhinoceros beetle is built for combat. His large horn has evolved especially for taking on rivals. Its size indicates his strength and health. And this male is very well endowed. At last, the highly prized sap. But someone else has got there first. And this large challenger won't be easily overcome. They are well matched in size and weaponry. The rival attacks from behind. But neither can overpower the other easily. Until... The territory is his. And he is rewarded with more than just sap. A female rhinoceros beetle. Victory has never been sweeter. For now, he can enjoy the spoils of war. In the DMZ, like everywhere in the natural world, we see familiar life experiences. Sometimes through very unfamiliar creatures. This monk has studied the animals in his forest home for years. Trying to understand what we can learn from the natural world. And what makes humans unique. A young boar has died by the river. His fate is uncomfortable viewing for any human observer. But wild boars are omnivorous. They will eat anything. Even their own kind. This behavior is rare but not unheard of among boar communities. In this respect, the boars of the DMZ are no different from anywhere else in the world. The environment of the DMZ is both natural and unnatural. Life occurs here between fences. Man-made impositions on the landscape. But it is only a glimpse of this mysterious place. The vast majority remains unexplored. And what else may exist here is only speculation. But there have been a number of unusual reports from soldiers on the front line. Reports too important to be ignored. The DMZ could be home to one of the rarest and most beautiful creatures on earth. The Amur leopard. There is no conclusive proof. But it is possible. As they once thrived throughout the Korean peninsula. To explore this mystery would require cooperation between north and south. What we do know about the DMZ is that it's an untouched wilderness. For the world to learn from. This special area exists in the space between two countries that have undeniably diverged over the past 65 years. But it is proof that north and south have a shared natural history. And proof of the resilience of nature. And its ability to transcend human conflict.