- This is not a normal highway bridge. Oh, my God. It's actually part of a massive effort to build one of the biggest wildlife corridors in the world: the Yellowstone to Yukon region, spanning five U.S. states, two Canadian provinces, and more than 75 indigenous territories. It's the size of a large country. Now, a hidden network of bridges, tunnels, fences, and whatever these are, has started to connect 11 huge national parks within this region, allowing wildlife to roam freely for the first time in generations. This is not only saving animal and human lives, but it will save billions of dollars of taxpayer money in the process. And it's only possible 'cause of a small team of scientists and nature lovers. So I'm here in the Rocky Mountains to find out how research and engineering emerging into one of the biggest rewilding projects in the world. And we're going to use this to capture the insane collection of creatures that are already using these passageways. We are Planet Wild. Welcome to Mission 36. (tense inspirational music) The Rocky Mountains, the largest mountain range in North America, a vast, largely untouched expanse. I just have to take a second to fully appreciate where I am, because I'm surrounded by forest and by mountain peaks like I've never seen before in my entire life. And it's incredible. (tense music continues) (graphic chimes) But I'm also a little bit worried about grizzly bears (quirky music) 'cause this is grizzly bear territory. And last week I was talking to a bear expert for some research and he said I wouldn't have a problem. - You won't have a problem. - But he also said some stuff that made me a little bit more worried. - I thought I was going to die. (Clayton laughs) - Thanks, Clayton. We'll come back to you later. Grizzlies used to be found all the way from the Arctic Circle in the north to down in Mexico. And just 200 years ago, (projector whirring) this landscape was completely uninterrupted, which is the blink of an eye in evolutionary terms. But now the range of the grizzlies has shrunk to just this corner of North America. And this is why. (train horn blaring) (track rattling) (truck horn blaring) This is the Canada Pacific Railway built in 1881, and during the colonisation of North America, this connected the east and the west coast of Canada. But it cut straight through this valley. And now imagine if you are a grizzly bear and you have to travel from this side of the valley to this side. And if a train goes past once an hour, imagine trying to cross a highway where a car goes past on average once every three seconds. (melancholic music) - It makes the world smaller for grizzly bears, and they have to increasingly navigate around those barriers. What it means is these bears basically never get old and die, like, there's essentially no natural mortality. If a bear's going to die in the Elk Valley, it's unfortunately gonna be at the hand of people. And half of the grizzly bears that died in our study were due to collisions with vehicles or with the train. - [Cameron] Recently there was a report of a young bear named Lingenpolter, who spent months trying to get across a highway. In fact, he tried and failed 45 times, only managing on the 46th attempt. - It's a real challenge to navigate this landscape. We've got power lines, canals, railways, highways, and housing developments, right? So it's a very complex landscape. - [Cameron] This is Bill Hunt from the Yellowstone to Yukon initiative, or Y2Y. Bill has spent his life working in Canada's wilderness, first as a park warden and then a conservation manager, always with the goal of protecting wildlife. Today with Y2Y, he's trying to create the biggest corridor for wildlife in North America and possibly the world. - The scale of Y2Y is huge. It's a big vision. It's a big, it's very ambitious, but it's completely achievable. - Y2Y has been working for more than 30 years to create a massive interconnected area starting from Yellowstone Park in the south, tracing the range of the Rocky Mountains around over 100 existing protected areas, including 11 national parks all the way up to the Yukon Territory in northern Canada. So the Y2Y vision is a massive interconnected area of 1.3 million square kilometres. And I was just looking up, trying to get an idea of how big that actually is. And apparently, if it was a country, it would be in the top 20 biggest countries in the world, right in between Peru and Mongolia. I mean, just look at it compared to the size of Europe, the scale of that, it's just huge. But in order to make this dream a reality, we need to get rid of all these roads. Okay, we obviously can't do that, but we can build new infrastructure for wildlife. So this behind me is a wildlife crossing, and it's specially designed to get animals over the highway safely. This bridge is basically built to carry a small forest. Thousands of tonnes of soil are piled on top, and then native bushes and trees are planted, so it blends perfectly into the landscape. And you might be thinking, that looks really expensive. Who's gonna pay for it? Well, it's actually more expensive without it. Every year in the U.S., there's around 2 million collisions with animals, and as well as the countless lives that are lost in these collisions, it also costs people $8 billion a year. But a wildlife crossing like this can reduce collisions by over 90%. (graphic clicking) How it works is that there's miles of fencing along here that funnelled the animals over the crossing. And honestly, I never thought I would get into fence design. But this is not just any old fence. (soft music) - One of the key elements is that there's a buried apron of chain-link fencing actually dug into the earth, and this keeps bears and wolves from digging tunnels underneath the fence, which would defeat the whole purpose. And then going up, this is the page wire, and you'll see that it's what we call graduated page wire. And so the spacing at the bottom is smaller to prevent small animals from getting through. And then when you get higher on the fence, we've widened that out so that you're saving on weight and cost. So it makes it as affordable as possible. And then right on the very top of this, you'll see that there's a high tensile cable supported on the top of the posts. And that's so that if a tree falls onto the fence, it doesn't damage the page wire. In the old days, we didn't have that. If a tree blew on, this would all get crumpled and mushed up. And it was really hard to get it back together. And now the tree just sits on the cable, you come with a saw, you can cut that off and everything's still working. - Yeah. - It seems subtle, but each of these things saves tonnes of maintenance over the long run. - Yeah. - Yeah. (bell chimes) - But to make our lives a bit harder, not every animal likes to go over the highway. And this is like an old highway bridge that is retrofitted with fences along the side to guide the animals down here. It's actually kind of peaceful almost, the noise of the highway is reduced significantly. And you can tell why some species like cougars and black bears actually prefer to cross underneath the highway. And you can tell that loads of animals are coming through here. There's deer tracks everywhere, and you can tell that these crossings really just work. And there are many more types of crossings, like there's tunnels for toads, canopy bridges for squirrels, and even this amazing little crossing built especially for salamanders. Throughout the Y2Y region, more than 200 crossings have been built so far, but there's still one stretch of road that's causing serious problems. (contemplative music) This is Highway 3. Its location makes it really strategically important. It's currently blocking the movement of wildlife, both from north to south and east to west. In fact, this highway is separating two populations of grizzly bears, which is bad news because with a smaller gene pool, these populations become way more vulnerable to environmental changes and disease. In a case like this, Y2Y brings all the necessary people together to identify where the crossings are needed and to build them. (soft electronic music) So the vision is to instal 27 new crossings, including three new overpass bridges that would connect these two grizzly populations and allow all kinds of wildlife to roam freely through here. Creating big infrastructure projects like this takes a huge amount of bureaucracy and massive amounts of government funding. So Y2Y needs lots of hard data to get the ball rolling. And that is where these come in. Camera traps lay the groundwork. They allow us to show how effective certain crossings are for different species, and they show us where animals are already trying to cross the roads. So the Planet Wild community is funding six extremely durable professional trail cameras to support the Highway 3 project, along with 15 of these new GPS wildlife collars for four different species. That's elk, mule deer, bighorn sheep, and, of course, grizzly bears. With the GPS data from these collars, researchers can pinpoint the critical places where new crossings should be built to ensure separated populations can find each other better. And whilst we're installing the cameras, I'm gonna tell you how we made this possible. Planet Wild is a global community of nature protectors. And every month we go on a mission to clean up our oceans, to bring back endangered species, and to rewild entire landscapes. And everything is community-funded. So if you wanna support projects like this, join Planet Wild as a backer. There's a QR code here and a link in the description. There we go. Done. - Perfect. - Amazing. (wind blowing) (feet thudding) Future Cam here. So Y2Y just sent me over some of the footage from the wildlife cameras, and I'm sitting here watching it, and I'm just thinking like, it's just... Okay, you know what, we're just gonna have to roll it. (bright enthralling music) Research has proven more than 150,000 animal crossings through these new structures, and it really hits you when you just take a second to watch the footage from these cameras. (bright enthralling music continues) - If they can find a safe spot, like an underpass or an overpass, they memorise that, they learn that, and they'll come back to that spot time and time again. (bright enthralling music continues) (bright enthralling music continues) - This footage is gonna push forward at the Highway 3 project. But it's not just about one highway, this is about reimagining how entire landscapes can work. And this vision is gonna take a lot of work, a lot of collaboration, and probably many decades to complete. For every single data point, every crossing and every animal that makes it across the highway safely is one step closer to making that vision a reality. So what can you do next? Well, join Planet Wild as a backer at the QR code here, or subscribe to catch our next mission. Thanks, and see you next time. (bright enthralling music continues) (bright enthralling music continues) (music fades)