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.
Explore the wild blue Caribbean waters of Cozumel, a lush paradise packed with marine surprises. From the spectacular Paso Del Cedral coral reef to the world's longest subterranean underwater cave system, go where only the bravest divers dare venture.
This is the story of two young animals forced to grow up fast. In Africa's savannah, a baby elephant shrew learns how speed is the secret to survival amongst the largest animals on Earth; and in America, a young grasshopper mouse confronts the Wild West's deadliest creatures to stake a claim of his own.
The era of the sabretooth and many other Pleistocene creatures comes to an end. The biggest big cats ever, the lion and the tiger, become the kings of their respective habitats - but they had to fight for their place. To survive, these great cats target larger and more challenging prey.
The fifth programme explores the alliances formed between the animal and plant worlds. It examines the ways in which plants live together and rely on each other. Whether living together in harmony, relying on each other for homes, protection or food, or living off each other, by strangling or otherwise destroying each other in a bid to survive.