The narrow strait between the Indonesian islands of Bali and Lombok marks the boundary between the wild worlds of Asia and Australia. This is the story of life on each side of nature's great divide.

The Wallace Line divides separate worlds, where radically different animals live remarkably similar lives. This is the story of two parallel creations, and what happens when these worlds collide.

Safe behind the Wallace Line, life in Australia charted its own evolutionary course, in habitats defined by natural borders. This is the story of the wild kingdoms protected by Nature's Great Divide.