In Bhutan, Palin finds himself back in the land of yaks for a last look at the high Himalaya. Trekking to Chomolhari base camp he meets a nomad with a penchant for yak songs before heading down to Paro to witness the Buddhist festival or Tsechu. In a bar in Thimphu, he discusses reincarnation and the pursuit of happiness with Benji and Khendum, two of the king's cousins, and en route to Bangladesh is taken by Benji to see the rare black-neck cranes. On his journey south through Bangladesh, Michael visits the ship-breaking beaches of Chittagong and grid-locked Dhaka. He meets a man who made a fortune in Birmingham in the poultry business, and a woman who lends money only to women. On a 1920s paddle steamer he is serenaded with the words of Bengal's Shakespeare, and he completes his epic Himalayan journey aboard a fishing boat that carries him out into the Bay of Bengal and a westering sun.

'Blood Brothers' follows the lives of two species, Paranthropus boisei and Homo habilis who embody two alternative ways of ape-man life. Although heavyset, with distinctive gorilla-like faces, the boisei are gentle characters. They live within a strict social structure and are led by a dominant male whose strength and power holds the group together. The habilis have taken a different approach to survival. They don't have the specialisms of the boisei but instead have developed into the archetypal jack-of-all-trades, inquisitive scavengers prepared to try almost anything to survive. Tough, active, gregarious and noisy, they are always on the move and always alert to the possibility of a meal. But in the near drought of the dry season the habilis are struggling. It seems as if their way of life cannot help them when conditions are tough.

Hernan Cortes left Cuba in 1519 seeking riches in the island to the west. Instead he discovered, and ultimately destroyed, a hitherto unknown civilization. Join Micheal Wood as he retraces this fateful expedition. Read Spanish eyewitness accounts that describe the conquistadors' awe at the Aztec achievements and the lust for native treasure. Learn the Aztec' side of the story by scrolling trough pictographs that tell of the agonizing fall of the empire.

Audrey Hepburn was a film and fashion icon of the twentieth century and one of the most beloved actresses of all time. She enchanted the world with elegance and innocent charm, and portrayed some of the most memorable characters in film. Although she was one of the few actresses to win an Emmy, Tony, Grammy, and Academy Award, Audrey was modest about her talents, often claiming she had no acting technique. She redefined glamour with elfin features and a waif-like figure that inspired timeless designs by Hubert de Givenchy.Raised in the Netherlands during World War II, Audrey never forgot her own struggles during the German occupation and dedicated her later years to helping needy children around the world, becoming an International Goodwill Ambassador for UNICEF and traveling around the world to provide aid. Audrey Hepburn is remembered as a natural talent, a timeless beauty and a great humanitarian.

The fifth programme explores the alliances formed between the animal and plant worlds. Attenborough dives into Australia's Great Barrier Reef and contrasts the nocturnal feeding of coral, on microscopic creatures, with its daytime diet of algae. Some acacias are protected by ants, which will defend their refuge from any predator. Besides accommodation, the guards are rewarded with nectar and, from certain species, protein for their larvae as well. Fungi feed on plants but can also provide essential nutriment to saplings (Mycorrhiza). The connection is never broken throughout a tree's life and a quarter of the sugars and starches produced in its leaves is channelled back to its fungal partners. Meanwhile, fungi that feed on dead wood leave a hollow trunk, which also benefits the tree. Orchids enjoy a similar affiliation. Lichens are the product of a relationship between fungi and a photosynthetic associate, usually algae. They are extremely slow-growing, and a graveyard is the perfect location to discover their exact longevity. Mistletoe is a hemiparasite that obtains its moisture from a host tree, while using own leaves to manufacture food. Its seeds are deposited on another by the mistletoe tyrannulet, following digestion of the fruit. The dodder (Cuscuta) is also parasitic, generally favouring nettles, and siphons its nourishment through periodic 'plugs' along its stem. The rafflesia has no stem or leaves and only emerges from its host in order to bloom — and it produces the largest single flower: one metre across.

This episode discusses the human exploration of Antarctica, in particular the mission led by Captain Robert Falcon Scott, whose team died on the way back from the South Pole. It shows the scientific work in the modern human bases in Antarctica, especially Mawson Base and its observation of Adelie Penguins (partially through tracking devices). The second half of the episode describes how the series was made. Most crucial was of course the camera work. To get access to the wildlife of the sea, for example, boats, divers, suspended capsules and remotely controlled cameras mounted on inflatables were used. Particularly dangerous to divers were Leopard Seals and other predators. The film concludes that although working in Antarctica is now much easier than during the early days of exploration, human footsteps on the continent are still exceedingly rare in part because of international treaties prohibiting industrial exploitation.