In 1912, the largest volcano eruption of the 20th century laid waste to one of the most pristine corners of Alaska. Today, the Valley of 10,000 Smokes has become a home to one of the largest bear populations in the world.
The hunt for life within the long-dead bones of dinosaurs may sound like the stuff of Hollywood fantasy - but one woman has found traces of life within the fossilised bones of a T rex. Dr Mary Schweitzer has seen the remains of red blood cells and touched the soft tissue of an animal that died 68 million years ago. Most excitingly of all, she believes she may just have found signs of DNA. Her work is revolutionising our understanding of these iconic beasts.
In this episode Brian uncovers how the stunning diversity of shapes in the natural world are shadows of the rules that govern the universe. In Spain he shows how an attempt by hundreds of people to build the highest human tower reveals the force that shapes our planet. In Nepal, honey hunters seek out giant beehives that cling to cliff walls. The perfect hexagonal honeycombs made by the bees to store their honey conceal a mathematical rule. Off the coast of Canada, Brian explains how some of the most irregular, dangerous shapes in nature - massive icebergs that surge down from Greenland and into shipping lanes of the Atlantic - emerge from a powerful yet infinitely small force of nature. Even the most delicate six-sided snowflake tells a story of the forces of nature that forged it.
This new age of discovery is revealing there is still so much to learn about the cat family. Using high-tech collars, Professor Alan Wilson has discovered it is not straight-line speed that is a cheetah's greatest weapon but their ability to break, change direction and accelerate. His research is rewriting what we understand about the fastest animal on land. This is also a crucial time for cat conservation - most are threatened, facing extreme habitat loss and conflict with humans. Yet there are many positive stories of cats bouncing back from the brink,