An old prophecy says that Great Bear Lake, a massive and largely untouched Arctic lake in Canada’s Northwest Territories, is where the world’s peoples will travel for relief when the rest of the planet becomes unlivable.

At more than 12,000 square miles (larger than the country of Belgium), Great Bear Lake is the eighth largest lake on Earth and the largest in Canada. It is also the most pure and untouched of the world’s lakes, despite the active fishing community of Deline, the only town on its shores.

The prophecy was made by a Sahtuto’ine (the indigenous Bear Lake people) elder named Eht’se Ayah. The prophet believed that, when the rest of the world’s food and drink supply has depleted, the lake’s purity and the availability of plenty of fish would attract so many people on so many boats that a person would be able to walk from boat to boat without entering the lake.

The indigenous people of Deline, for whom the lake is sacred, take the responsibility of caring for such an important destination very seriously. In March of 2016, Great Bear Lake and the surrounding area became the largest UNESCO Biosphere Reserve in North America, and the Canadian government gave Deline the right to govern itself, ensuring that the indigenous people are charged with its care.

The spiritual connection to the lake traces from the “water-heart story,” about an ancient fisherman who turned into a fish to chase another fish into the lake and retrieve a fishing hook. At the bottom of the lake, the fisherman saw a gigantic beating heart. To some, this legend suggests that the lake not only gives life to the surrounding area, but all of the natural world.

Grizzly Bear Mountain is on one of the lake’s peninsulas, and the name Great Bear Lake is likely a mistranslation of North Slavey (the native language of the area) for “grizzly bear lake.” The five arms of the lake are named Dease, McTavish, McVicar, Keith, and Smith, after members of the Hudson’s Bay Company, fur traders who helped explorer Sir John Franklin on his expedition to the area in the early 19th century. They were among the first people to play hockey in Canada, on a frozen Great Bear Lake.

Of the 16 species of fish in the lake, some species only live in one of the lake’s arms, since the lake is so large the fish do not tend to migrate. On land, the wildlife includes caribou, moose, grizzly bears, and musk oxen. The lake straddles the Arctic Circle, and is frozen most of the year. It also experiences the midnight sun during the summer months.