In recent years, close study of the aging process has opened up new ways that could help us all live healthier for longer. Can we move beyond treating individual diseases, and instead treat the aging process itself? But would a longer life necessarily be a better life? A loose-knit group of researchers believe the real breakthrough is extending our health span - the period of life spent free of disease". Hear from Laura Deming, who dropped out of M.I.T. at the age of 14 and committed herself to finding and funding projects that can expand the human health span, and Dr. Brian Kennedy, whose work in the basic biology of aging has been crucial to the development of countless other researchers' work.

Between 1850 and 1950, three cataclysmic revolutions shook China to the core, but out of them, today's China emerged. The film begins in Canton with the meeting of a US missionary and a Chinese student. Inspired by the Christian story and calling himself God's second son, Hong unleashed the bloodiest war of the 19th century, the Taiping Rebellion.
As imperial China weakened, foreign influence grew. Treaty ports expanded, bringing growth and wealth, trams, railways and western sensibilities. But this provoked another surge of violence, the Boxer Rebellion, an attack against the foreigners, which was crushed by those same foreigners, who extorted a huge indemnity - $60 billion in today's money.
Then in 1912, the empire fell, and many groups contested China's future. In World War I, China sent 100,000 men to the western front, only to be humiliated at Versailles when German colonies in China were handed to Japan. Between the two world wars, the disparity between rich and poor, city and countryside increased. We visit Hong Kong's Peninsular Hotel in the jazz age and then follow Mao on the Long March to Yan'an, the heartland of revolution.
World War II came to China two years earlier than it did in the west. Wood talks to a survivor of the Japanese massacre of Nanjing in 1937 and then charts the triumph of the communists, before ending the story with Mao's death and the boom time of the last 30 years. The series ends with the warmth of the Chinese family and, at Beijing's Altar of Heaven, a final haunting glimpse of eternal China.

Quinto sets out to discover whether aliens exist and what evidence we have to prove it. He meets with several who say they have encountered extra-terrestrial life–a man who has been abducted by aliens several times since childhood; a man who claims to have extracted an alien implant; and a woman who shows Zachary what it feels like to be abducted into a spacecraft.
Zachary also meets with the world's leading scientists at SETI in Green Banks, West Virginia. There, utilizing the world's largest telescope, they show him the methods they employ to communicate with potential other-worldly visitors and what this research has taught them about a mysterious radio signal they picked up 3 billion light years away.

The images of brothers Tamerlan and Dzhokhar Tsarnaev are released to the public setting off a violent chain of events. Meanwhile, clues from their past tell a complicated story - how was the radicalization of the ethnically Chechen brothers and the existence of potential collaborators. The post-9/11 biases played a role in the investigation.

The fourth episode starts off with the two riding through Santa Cruz, Argentina. The plan is to cross over into Chile and then going up into the Andes. Ewan and Charley head through Argentina’s red rock landscape while a member of their team copes with altitude sickness. The duo are well and truly underway and the first signs of all are well is how well the Harleys hold up in challenging conditions. The roads alternate between unforgiving and pleasant and these e-bikes push through effortlessly. As they ride through Chilean Andes, the audience is shown a picturesque view of the beauty of the countryside, an experience which Boorman calls 'magical.'

The Arctic is the harshest environment on Earth: little food grows, it's dark for months on end, and temperatures stay well below freezing for much of the year. Yet four million people manage to survive here. Human Planet tells remarkable stories of extraordinary people who make their homes in nature's deep freeze. In springtime, Amos and Karl-Frederik set out across the sea ice with their dogs to catch a real-life sea monster: a Greenland shark! Inuit mussel-gatherers venture underneath the sea ice at low tide for a perilous race against time as they gather their food. And the children of Churchill, Manitoba, set out on the most dangerous trick or treating Halloween in the world: they risk coming face-to-face with deadly polar bears on the streets of their town. Who'll get the tastiest snack?