Dr. Brady Barr comes face to face with earth's largest land-based predators. Deep in the Alaskan rain forest, he tracks brown bears armed with incredible strength, capable of running 30 mph. To fully experience this predator's ability, watch a 1,500-pound bear attack Brady - from the safety of a cage. Then, we'll explore a town where massive polar bears walk right down the street and see how locals cope with the dangers.