Carter's dreams of change give way to Ronald Reagan. Gorbachev redeems Reagan and fresh opportunities for peace arise. The debate over Reagan's legacy.

From virtually the moment we're born, there's a story that's preached across cultures and continents. It's a familiar fairy tale, that finding one true love is the key to a fulfilled and happy life. As an adult, we're forced to reconcile the messaging on monogamy with one simple fact: humans are terrible at it.
What do biology, human history and the promiscuity of bonobos reveal about monogamy? Experts and everyday couples weigh in on shifting cultural norms.

This episode explores what can give brains a boost. In America, Angela tries out a new treatment that's proven to help memory and concentration. In Japan, a remarkable 100-year-old reveals the colourful foods that keep minds more active. Plus Chris discovers the best exercise we can do for our brains. At the cutting-edge of science, discover how injections of young people's blood may help beat dementia.

We routinely talk about healthy food and clean water, but how often do we spare a thought for what enters our lungs? The World Health Organization calls air pollution the silent killer. Air pollution is proven to shorten our lifetimes and it hits the vulnerable - children, the sick and the elderly - hardest of all.
Prince William, Sir David Attenborough and astronaut Naoko Yamazaki hear the personal stories of people who are directly affected by air pollution and show us incredible solutions.

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.

To fly like a bird, Earthflight not only captured remarkable images of wild flocks but also relied on some extraordinary relationships between people and birds. Filmed over four years, in six continents and more than 40 countries, the Earthflight team used many extraordinary techniques. For some of the unique flying shots, members of the team became part of the flock. The birds followed wherever they went - even in a microlight over Edinburgh and London. In Africa, paragliders floated alongside wild vultures, while a model vulture carried a camera inside the flock. In South America, wild-living macaws, that were rescued as babies, still come back to visit their 'foster mother' as he travels along a jungle river. In Africa, a radio-controlled 'drone' silently infiltrates masses of pink flamingos without disturbing a feather, and microlights and helicopters capture the dramatic moment white storks arrive over Istanbul. In Africa a tame vulture carried a camera across the African bush and recreated the behaviour of his wild relatives. Similarly, in the USA, a flock of hand-reared snow geese followed the migration route of wild flocks and took in the sights and sounds of New York - managing to get lost in Brooklyn