加拿大：荒野年轮 Canada: A Year in the Wild

Canada is the second largest country on Earth, and the quintessential wilderness. Vast, dangerous and magnificent; it’s a land of towering mountains, endless forests, untamed rivers, enchanting lakes, and an awe-inspiring frozen north. 　　To survive here animals have to be tough, and Canada has some of the toughest. Industrious beavers have mastered control of its myriad waterways...