This woodland construction is the world's biggest beaver dam, which at 2,790ft is more than twice the length of the Hoover dam and can be seen from space. The mammals use trees, mud and stone to make a type of moat where they can use their swimming skills to evade any predators. The families live in lodges on the dams and spend their days adding to and repairing the incredible structures. The dam was spotted by experts monitoring the size and spread of the beaver dams in North America. It is located on the southern edge of Wood Buffalo National...