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.

More than 90% of all crashes have a human driver as the cause. So if you want to solve traffic fatalities, the best solution is driverless vehicles. It's an ambitious goal, but only possible because of the recent breakthroughs in deep learning. Artificial intelligence is one of those key pieces that has made it possible now to do driverless cars where it wasn't possible ten years ago. For computers, until very, very recently, to do even the most basic visual tasks, like seeing a picture of a person and knowing that it's a person was remarkably hard. That's obviously fundamental to being able to understand the world around you with the sensors that you have. And we've made also gigantic strides in being able to perform complex tasks.

North Korea, formerly known as the hermit kingdom, is perhaps the largest source of instability as regards world peace. Its border is one of the most militarized in the world. The lack of impartial information, both inside and coming out of the country, is the perfect setting for a propaganda war, which will be analysed in the film through numerous examples of the surprising way in which information is manipulated, in and about North Korea. Alejandro Cao de Benos, the sole foreigner who works for the People's Republic of Korea Government, and many locals will show us their vision of the reality in North Korea. The other side of the story will be reflected through interviews to South Korean citizens, human rights advocates, diplomats, propaganda experts, etc.

A ground-breaking new trial at Imperial College London sees, for the first time ever under controlled conditions, a psychedelic drug tested head-to-head against a standard antidepressant as a treatment for depression. The film follows a pioneering team of scientists and psychotherapists as they compare the effects of psilocybin (the active ingredient of magic mushrooms) with an antidepressant on a small group of participants with clinical depression.
This is scientific research at its most cutting edge. With over seven million people being prescribed antidepressants each year in England alone, this drug trial is an important milestone in understanding a completely different treatment for depression. How do psychedelic drugs measure up against the industry-standard antidepressants that have been popular since the 1990s? The empirical results of the trial are explored alongside the participants’ powerful lived experience.

Oscar-winning filmmaker Oliver Stone was granted unprecedented access to Russian president Vladimir Putin during more than a dozen interviews over two years, with no topic off-limits. This remarkable four-part documentary series provides intimate insight into Putin's personal and professional lives, from his childhood under communism, to his rise to power, his relations with four U.S. presidents, and his surprising takes on U.S.-Russian relations today. Witness the most detailed portrait of Putin ever granted to a Western interviewer.

The definitive story of cinema’s most iconic figure, from an impoverished childhood in London through a spectacular rise to fame, until his scandalous fall from grace and a self-imposed exile. His stage persona and incendiary media portrayal defined how he was perceived, but his private life has always been shrouded in mystery - until now. Never-before-heard recordings, intimate home movies and newly restored classic films reveal a side to Chaplin that the world never got to see.
Filmmakers Spinney and Middleton shed light on Chaplin’s family life, his contentious relation to the political commotions of the 20th century, and artistic genius.