13/13 How the Highlands' moorland and forest are both crucial to their wild inhabitants.
12/13 Steve Backshall discovers kangaroos, the world's most venomous snake and a burrowing toad.
11/13 Steve Backshall plumbs the ocean depths to find an array of bizarre creatures.
10/13 Steve Backshall looks for the answer to a puzzle involving wolves and beavers.
9/13 Steve Backshall looks at life in the oldest desert in the world, the Namib in Africa.
8/13 Steve finds out how a tiny coral building block created Earth's largest living structure.
7/13 Why Canada's coastal forest is home to top predators like eagles, bears and wolves.
6/13 Steve Backshall unravels the secrets that lie covered in ice for most of each year.
5/13 Steve Backshall reveals the secret to the existence of the world's largest inland delta.
4/13 Steve Backshall looks at the unique geography of California's Monterey Bay kelp forest.
3/13 A look at intricate relationships and unexpected hardship in the Amazon rainforest.
2/13 What is the key to the Serengeti that allows such density and diversity of herbivores?
1/13 How did the unique wildlife of the Galapagos get there and what allows them to thrive?