Northern Canada’s beavers used branches and mud to slow floodwaters; their 850-meter dam that can be seen from space transformed the forest into a pond holding 70 million liters of water over time

A beaver dam hidden deep in northern Canada is so large that satellites can see it from orbit. The structure sits inside Wood Buffalo National Park, far beyond roads and established trails. Its front edge stretches about 775 meters across the landscape. The pond behind it holds an estimated 70 million liters of water, turning a remote forest into a vast wetland.

Getting there is another story entirely. The dam lies among wetlands, muskeg and thick boreal forest in one of Canada's most remote protected areas. A person attempting the journey would face difficult terrain for days. That isolation explains why the structure was discovered from above rather than during a routine field survey.