Episode list

Deep in the heart of the Guatemalan lowlands, with the aid of LiDAR technology, archeologists identify an ancient site made up of a previously unknown series of structures. These structures include what appear to be a temple, a palace and housing platforms that are similar to the other Maya ruins in the area. However, scans reveal a network of stone walls, ditches and towers in the surrounding area that are entirely unfamiliar to Maya experts. If it wasn't the Maya, then who built these structures and why? In the middle of the South Pacific, in the heart of a deserted tropical island, is a lake that is home to millions of jellyfish. In fact, the lake ¬- known to the locals as Ongeim'l Tketau, the fifth lake ¬- has the highest concentration of jellyfish in a body of water anywhere in the world. Jellyfish are normally salt water creatures found in seas and oceans in all corners of the world - lakes are not their preferred habitat. Where did all the jellyfish come from? In the remote reaches of Argentina's northern jungles, on the border with Paraguay, sits the provincial park of Teyú Cuaré. A group of archaeologists are examining a series of three stone structures, hidden beneath dense undergrowth. Although they are in a state of disrepair, the ruins are unmistakably built to house people. When the archaeologists examine further, they are shocked to find a swastika engraved on one of the walls. Could this have been a place inhabited by Nazis fleeing prosecution in Germany? A group of biologists conducting field research in the remote rainforest of Maninjau in Indonesia's western Sumatra become aware of a putrid stench enveloping them. Thinking that there is probably a dead animal, or worse, a dead human, they investigate. They are shocked to discover that the smell is emanating from a flower. But not just any flower, an enormous flower, measuring some four feet in diameter. What kind of flower is this? And why does it give off such an awful smell?

In the rainforests of Belize's Tapir Mountain Nature Reserve, lies the entrance to a mysterious cave. Deep underground, researchers discover a complete and curious skeleton that is delicate in size and entirely coated in crystalline growth as if it were bejeweled. It has an alien, elongated skull that has been crushed. Could these be human remains or something else? On the mountain plateau of Phnom Kulen, Cambodia, archaeologists conducting a LiDar survey find something astonishing - a network of roads, boulevards, earthworks and other structures that indicate the presence of a highly advanced and thriving population inhabiting this remote plateau. Who could have built all of this? In Australia's far north, bordering the rainforests of the continent's coastline lies the Wessel Islands, an archipelago that extends for miles off what is known as Arnhem Land. A group of researchers patrolling the island notice a small circular piece of metal peeking out of the sand in the intertidal zone. Its shape and weight indicate that it must be a coin, but it appears very old and is without markings. What kind of coin is this? And how did it end up here? In the Bolivian rainforest, local farmers clearing the thick jungle for farmland find something unusual buried in the earth below. As trees are uprooted, they uncover a large circular ditch that had been hidden by the thick undergrowth. It's 30 feet in diameter, made of rock with raised earth around the edges. It appears to be man made, however the rainforest has been growing untouched in this area for centuries. What could this unusual formation be?

On the island nation of Sri Lanka, 600 feet atop a granite rock column surrounded by overgrown rainforest, lies a structure built in the sky known only to the pages of hallowed Buddhist texts for over a thousand years. What could these ruins be? Excavations of the Maya ruins of El Palmar, a small plaza compound near Chiapas, Mexico reveal the curious remains of a small man. This area, thick with jungle and dotted with ruins, is in the heart of the once thriving Maya empire. Who was this man? On the southwest shore of Costa Rica, lies the Diquís Delta, where over 300 stone spheres, often referred to locally as Las Bolas, appear scattered at random. The Diquís Spheres range in size from just a few inches, to over 6 feet in diameter. How did these almost perfectly shaped stone balls end up in the Costa Rican jungle? The Mahajanga Basin on the island of Madagascar, 250 miles from continental Africa, is home to a treasure trove of fossils. Among thousands of paleontological discoveries of reptiles, fish and plant life, a team of scientists discover an intact fossil unlike any known animal, living or extinct. What is this mysterious beast?

In the tropical lowlands of Northern Colombia, a huge coal mine known as Cerrejón lies at the centre of the empty, forbidding outback. A team of scientists on an expedition in the mines uncover a number of animal bones, and among them is a bone they can't identify. A massive vertebra too large to belong to any jungle animal on record. What imposing creature could this giant backbone belong to? The lush rainforest of southwestern Cambodia's Cardamom Mountains stretches 4.4 million hectares and is so remote it can only be reached by helicopter. A conservation surveyor working in the area encounters a former soldier who is carrying ornate jars he had found in the mountains. The jars are tightly packed with bones and there are 40 others, balanced on ledges 300 feet above the jungle floor. Who or what did these bones belong to? In the Pacific country of Palau lies the small volcanic island of Peleliu. It can only be reached via airplane or a two and a half hour boat ride. A tourist taking photos in the jungle discovers a large, rusted metal object. It looks like a vehicle of some sort, but it's odd shape makes it difficult to identify. What is this thing? Southeast of Quito, Ecuador's capital, is the spectacular forest of the Unesco Sumaco Biosphere Reserve. The forest is home to some peculiar looking palm trees called the Socratea Exorrhiza. Characterized by their thin trunks that grow out of a series of above ground roots, it almost appears as if these trees are on stilts. When a biologist begins studying the forest for conservation purposes, he discovers something odd ¬- it looks like the trees are slowly moving in a new direction on a daily basis by themselves. Is that possible?

A group of archeologists surveying an area in the remote Cagayan Valley on the Philippine island of Luzon come across some curiously shaped stones and bones scattered on the ground and decide to investigate further. After digging a few feet into the soil, an almost entirely intact animal skeleton reveals itself. They determine that the skeleton is from a rhinoceros and it has marks on its limbs and ribs. Was this rhino killed and butchered by someone in the Stone Age? Adventurers visiting Panama hike to Palo de Letras, an unmanned stone obelisk that marks the Colombia-Panama border, the invisible line separating North and South America. In the middle of nowhere, they stumble on an incomprehensible site ¬- a rusting wreck of a car abandoned to the jungle. The area is a stretch of tangled rainforest, mountains and swamps with no roads to speak of. How did a car end up in this treacherous region? Twenty miles from Sao Paolo, Brazil is the beautiful island Ilha da Queimada Grande. But if you look closer, this island paradise turns into something terrifying - it's covered with Golden Lancehead Vipers, between 2,000 and 4,000 of them. There are so many, some experts estimate that you'll find a snake for every three square feet. How did so many deadly snakes end up on this small island? Approximately nine miles from the Kenyan coast, surrounded by tropical forest, sits the impressive Panga ya Saidi limestone cave complex. There, researchers make a shocking discovery - human remains deep in the cave 10 feet below the surface. Who do these remains belong to?

In the northwestern Pacific, near the shore of Pohnpei in the Federated States of Micronesia is a lush green island that holds a massive, mysterious structure hidden beneath dense vegetation. When a tourist sets out to explore the island, they notice that it isn't just one structure, but 99 islets near each other. What was this place? On the northern coast of the island of New Guinea, an unsettling sight is revealed on a steep hillside beneath the canopy - scattered bits of charred metal and broken glass lead to what resembles the tail section of a plane, decaying in the humid climate. Whose plane is this? And where did it come from? India's Western Ghats, located 2.5 hours from Mumbai, is a mountain chain that contains some of the best examples of tropical evergreen forests anywhere in the world. Hikers exploring the forest at night stumble upon something astounding - hundreds of glowing green lights on the forest floor and in the trees. What is causing this strange phenomenon? In western Brazil, near the Bolivian border, a scientist working on a geological survey in a forested area comes across an unusual hole in some rocks. Exploring further, he discovers that the hole is actually the entrance to an enormous underground tunnel system stretching almost 2000 feet deep into the hill. What is this incredible place?

A farmer in central Belize hears screams coming from the nearby jungle and rushes to the scene, only to find a looter who had fallen 60 feet into a large cave. A rescue team is summoned and is shocked to find hundreds of smashed up human bones and teeth scattered across the cave floor surrounding the looter. What gruesome incident happened here? In the western region of India, in a chain of forested hills and mountains, workers are repairing an old well near a village when they discover some strange cylindrical tubes buried in the mud. As they dig deeper, they are shocked to find more than a thousand of them. What are these tubular pipes? Why are there so many at the bottom of an old well? The rainforest around Lake Eacham, in Queensland, Australia is the oldest, continuously surviving tropical rainforest on earth. A scientist on a hike hunting for mushrooms in the region happens on a bizarre sight - a small, mouse like creature that appears to glow in the dark. What is this mysterious animal? Easter Island in the Pacific Ocean is famous for the massive stone heads that dot the landscape. Researchers on the island are surprised to discover 400 of these enormous creations in a small area as if abandoned or forgotten, while other statues were painstakingly transported as far as six miles across rugged terrain. Why were so many stone heads left in this one place?

In the rainforest off of Guatemala's northern lowlands, ancient Maya sites and monuments follow the Pasión River. A group of archaeologists tracing water channels at the Maya site of Cancuen make a grisly discovery in a mud filled reservoir - hundreds of human bones. What happened here? Shalala, Oman is a port town home to frankincense trees, desert sands and mountains. A young drone photographer attempts to capture footage of the desert nearby and is astonished to find that this once arid region has suddenly transformed into a lush rainforest. How is that possible? Australia is usually associated with the dryness of the outback, but in Kuranda, Queensland there's a dense rainforest that is a popular camping attraction. When a large tree that interferes with tents on a campground is removed, something shocking is revealed ¬- giant bones. What animal do they belong to? Could they have discovered a dinosaur? Off the coast of southern Tanzania, the tiny Kilwa Island is a maze of mangroves, swamps and palm trees. On the northeast coast, huge blocks of stone protrude out of the greenery overlooking the Indian Ocean. Spanning across a hectare on this flat ground, it seems like someone went to great lengths to build this massive stone site. What is this place?

In the southwestern Pacific Ocean, a mythical volcanic island called Kolombagara rises out of the sea. Among the palm trees, a cave is found to contain curious items - boots, a helmet and a broken bowl. It becomes clear that this cave was not formed by nature, but rather is the result of human labor. Who trekked through the dense jungle to dig a tunnel here? The Vu Quang Nature Reserve sits in the Annamite Mountains on Vietnam's north central coast. A surveyor conducting research in the region discovers two long, slender trophy horns and two skulls from an unknown animal. What animal do these skulls and unique horns belong to? The immense Rising Star Cave complex in South Africa is a labyrinth of passageways, chambers, tunnels and underground rivers. Some areas of the cave system are nearly impossible to access, which is why researchers exploring the complex are shocked to find bones in a tiny crevice off of an extremely narrow chamber. Who do these bones belong to and how did they get here? Near the town of Port Kaituma in northern Guyana, backpacking tourists stumble on a rusted-out crane truck deep in the jungle. The strange truck is knocked on its side, blanketed in vines and appears to have been looted for metal and parts long ago. How did this truck end up here?

In the jungles of southern Mexico, a rancher is out looking for an escaped cow when he comes across a cave mouth that leads twenty feet into the earth. Curious, he climbs down and is shocked to discover dozens of skulls and bones lying in piles on the cave floor. What could have happened here? On the plains of central Bohol, a Philippine island, a group of researchers exploring the area come across a strange sight - littering the landscape are countless perfectly conical shaped grass covered domes extending as far as the eye can see. What could they be? On Kauai Island, Hawaii, archaeologists investigating a steep cliff come across dozens of carved stone figures that look like nothing else they have previously found in Hawaii. The sculptures have disproportionately big heads with bulged eyes and flattened noses. Who made these and why? Along the Tambopata River in the rainforest of southeastern Peru, a scientist notices a bizarre-shaped structure attached to a blue tarp above him - tiny white parallel silk strands circled around a stalk-looking cone. Measuring only 2 centimeters across, it must be the work of an insect, but it's unlike anything he's ever encountered. What is this strange formation?