Over seventy stone, more than four feet tall at the shoulder, sporting four-inch claws and paws that can dwarf a lion s... the world's biggest bears are the largest land-dwelling carnivores on Earth. Adult polar, brown (Grizzly) or black can take down just about any animal they want, including human beings. That's only part of their power: they can run as fast as horses and faster than Olympic sprinters, smell seals hiding under feet of snow and bite through thick tree branches. They re smart enough to get just about any food they want anywhere they find it. National Geographic gets as close as anyone dares to the world s biggest bears for a full profile of bear power. One-on-one with this biological juggernaut and deconstructs the muscle-and-bone mechanics that endow the Ultimate Bear and reveal a bear's exceptional survival secrets. Using CGI combined with cutting-edge imaging of bear brains; we also look inside these creatures and examine the bio-engineering of the world's biggest bears endowed not just with size, speed and power but powers of sensory detection that may be the best of any animal on earth. We will also look beyond their sheer size and ferocity to unpack the real complexity of bear power and overturn conventional thinking about these magnificent creatures.