From lush cloud forests to bare summits that take your breath away, the higher you climb the tougher life gets on a mountain. Human Planet explores the extraordinary ways in which people survive at extreme altitudes where nature becomes utterly unforgiving. In the Altai Mountains in Western Mongolia the vast open spaces make hunting for animals almost impossible, so the locals have forged an astonishing partnership with golden eagles which can do the hunting for them. On the precipitous cliffs of the Simien Mountains of Ethiopia we join a young boy locked in a dramatic battle with fearsome gelada monkeys which are hell-bent on raiding his family's meagre grain harvest. In the Himalayan state of Nepal - the roof of the world - we witness a rarely seen ceremony: a sky burial. In a land where there is little wood to burn for cremation, and where burying the dead is virtually impossible, the dead are fed to vultures in the ultimate reverence of nature.

Rivers provide the essentials of life: fresh food and water. They often provide natural highways and enable us to live in just about every environment on Earth. But rivers can also flood, freeze or disappear altogether!Cities - Surviving the Urban Jungle Human Planet joins Sam Niang, a Laotian fisherman, as he walks a high wire strung above the raging Mekong River rapids on an extraordinary commute to work. There's also a look at the remarkable partnership between Samburu tribesmen and wild elephants in their search for water in the dried-out river beds of Northern Kenya. Plus, a father who must take his two children on a six-day trek down a frozen river - the most dangerous school run on Earth, and the ice dam busters of Ottowa with their dynamite solution to a city centre hold-up.

The self-proclaimed 'Islamic State' is a jihadi militia active in the north and east of Syria, and in the west of Iraq, which has shocked the world with its cinematic staging of horrific acts of violence and its unexpected advances towards statehood. But why could IS expand so rapidly?

Researchers discuss mythic ancient treasure and curses including King Solomon's Ring, lost Aztec treasure, and the Omphalos.

In ancient Greece the Asclepian healing temples recognized the power of the primordial spiral which is symbolized by the rod of Asclepius. To this day, this symbol of our evolutionary energy remains as the logo of the American Medical Association and other medical organizations worldwide. The snake, the downward direction, is the manifested spiral, the evolutionary energy of the world.

If you had less than one second to make a life-or-death decision to shoot a man who might be armed with a lethal weapon, what would you do? Would the ethnicity of the man affect your decision? Are you sure? The outcome – whatever your race – will surprise you. Brain imaging studies are showing that negative cultural stereotypes hijack everyone’s subconscious decision-making. But some science says we can overcome bigotry through exposure, self-awareness and flexible social networks… and, most controversially of all, ultra-violent video games!