Competition to win a partner …has created some of the most extraordinary beauty and life-threatening violence anywhere in nature. Dazzling colours, elaborate dances and powerful weapons have all evolved to attract and defend a mate. The stakes could not be higher: without a mate, the journey of life ends here... sometimes literally.

A group of Egyptian revolutionaries battle leaders and regimes, risking their lives to build a new society. The Egyptian Revolution has been an ongoing rollercoaster over the past two and a half years. Through the news, we only get a glimpse of the bloodiest battle, an election, or a million man march. At the beginning of July 2013, we witnessed the second president deposed within the space of three years. The Square is an immersive experience, transporting the viewer deeply into the intense emotional drama and personal stories behind the news. It is the inspirational story of young people claiming their rights, struggling through multiple forces: from a brutal army dictatorship willing to crush protesters with military tanks, to a corrupt Muslim Brotherhood using mosques to manipulate voters. Directed by Jehane Noujaim, the film was nominated for the Academy Award and also won three Emmy Awards.

Austrian director Michael Glawogger travels to five countries to focus on some of the worst jobs imaginable: Ukrainian miners crawl into tiny cracks in old coal pits to scratch out a few bags of winter fuel; Indonesian workers trudge long distances carrying baskets with hundreds of pounds of sulfur chunks extracted from a steaming mountain; Pakistanis risk explosions and burial under tons of scrap iron as they dismantle huge carrier ships. The visuals are everything here. Despite the hardships depicted, many sequences have a dreamlike beauty. In addition, the director has a bone-dry sense of irony; during the Ukraine scenes, he frequently cuts away to a statue of Stakhanov, the "hero" lauded by the Soviets for his superhuman work habits. He also shows us an old German smelting works that's been converted into a theme park.

In ‘Who will we be?’ Dr. David Eagleman journeys into the future, and asks what’s next for the human brain, and for our species. We stand at a major turning point, one where we might take control of our own development. We face a future of uncharted possibilities in which our relationship with our own body, our relationship with the world, the very basic nature of who we are is set to be transformed. For thousands of generations, humans have lived the same life cycle over and over. We are born, we control a fragile body, we experience a limited reality, and we die. But science and technology are giving us tools to transcend that evolutionary story. Our brains don't have to remain as we have inherited them. We are capable of extending our reality, of inhabiting new bodies, and possibly shedding our physical forms altogether. And we are discovering the tools to shape our own destiny. Who we become is up to us.

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.

What might happen if the first manned mission to Mars crashes hundreds of miles from the rocket that would take them back home? Could they survive the crash, and travel across the brutal Martian surface to their home ship? We'll show what the astronauts would have to do to survive dust storms and space radiation, while extracting vital resources like water from the Martian soil itself. It's a dramatic vision of the very near future, where survival can depend on pre-industrial technology and human ingenuity.