Morgan Freeman continues to challenge audiences to think about daring topics in the last season of Through the Wormhole. In the part 1, new research is beginning to reveal a hidden force in the universe - one that penetrates space with trillions of invisible connections, instantly linking every place in our world and joining our future with our past. Is the Force with us?

Physicist Jim Al-Khalili travels through Syria, Iran, Tunisia and Spain to tell the story of the great leap in scientific knowledge that took place in the Islamic world between the 8th and 14th centuries. Its legacy is tangible, with terms like algebra, algorithm and alkali all being Arabic in origin and at the very heart of modern science - there would be no modern mathematics or physics without algebra, no computers without algorithms and no chemistry without alkalis. For Baghdad-born Al-Khalili, this is also a personal journey, and on his travels he uncovers a diverse and outward-looking culture, fascinated by learning and obsessed with science. From the great mathematician Al-Khwarizmi, who did much to establish the mathematical tradition we now know as algebra, to Ibn Sina, a pioneer of early medicine whose Canon of Medicine was still in use as recently as the 19th century, Al-Khalili pieces together a remarkable story of the often-overlooked achievements of the early medieval Islamic scientists.

The big blue is the world's greatest wilderness, far from shore and many kilometres deep. It's a vast marine desert where there is little to eat and nowhere to hide. Yet it's home to some of the biggest and most spectacular creatures on earth. This episode reveals what it takes to survive in this savage and forbidding world. We witness feats of incredible endurance, moments of high drama and extraordinary acts of heart-wrenching self-sacrifice. Every animal in the big blue must find their own unique way to survive. Sperm whales have the largest brains in the world. They live for 80 years, and we are only now beginning to learn the extraordinary complexity of their language of clicks - thought to coordinate the whole family in everything from childcare to hunting. With special pressure-proof cameras, we witness record-breaking feats of endurance as they hunt for squid a kilometre down into the abyss. Only recently have we begun to solve the mystery of where baby turtles disappear to in their early years. They leave the crowded waters of the coast and head to the open ocean, where they use floating debris like logs as life rafts. Here they remain until adulthood, adrift on the high seas in relative safety away from coastal predators. Over half of all animals in the open ocean drift in currents. Jellyfish cross entire oceans feeding on whatever happens to tangle with their tentacles. The jelly-like Portuguese man-of-war can harness sail power to fish with its deadly tentacles. Sometimes there is a brief explosion of food in this marine desert, but ocean hunters must be fast to make the best of this bonanza. We witness super pods of up to 5,000 spinner dolphins racing to herd vast shoals of lanternfish, briefly caught at the surface where it is thought they spawn. New aerial footage reveals, for the first time, the truth to a centuries-old sailors' legend of the 'boiling seas' - the spectacular feeding frenzy of 90kg tuna and dolphins smashing through the lantern fish shoals turning the sea white with foam.

Michael Wood tells the tale of China's first great international age under the Tang Dynasty (618-907). From the picturesque old city of Luoyang, he travels along the Silk Road to the bazaars of central Asia and into India on the track of the Chinese monk who brought Buddhism back to China. This tale is still loved by the Chinese today and is brought to life by storytellers, films and shadow puppet plays. Then in the backstreets and markets of Xi'an, Michael meets descendants of the traders from central Asia and Persia who came into China on the Silk Road. He talks to Chinese Muslims in the Great Mosque and across town hears the amazing story of the first reception of Christianity in 635. Moving south, Michael sees the beginnings of China as an economic giant. On the Grand Canal, a lock built in 605 still handles 800 barges every day! The film tracks the rise of the silk industry and the world's favourite drink - tea. Michael looks too at the spread of Chinese script, language and culture across east Asia. 'China's influence on the East was as profound as Rome on the Latin West', he says, 'and still is today'. Finally, the film tells the intense drama of the fall of the Tang. Among the eyewitnesses were China's greatest poets. In a secondary school in a dusty village, where the Chinese Shakespeare - Du Fu - is buried in the grounds, the pupils take Michael through one famous poem about loss and longing as the dynasty falls. And in that ordinary classroom, there is a sense of the amazing drama and the deep-rooted continuities of Chinese culture.

China's last empire, the Qing, lasted from 1644 to 1912. It began in violence and war as the Manchus swept down from the north, but invaders became emperors, with three generations of one family ruling the country. Among them, Michael Wood argues, was China's greatest emperor - Kangxi. Under the Qing, China doubled in size to include Xinjiang in the far west, as well as Mongolia and Tibet, creating the essential shape of China today. The new dynasty tolerated a diversity of cultures and religions, including Islam. In Kaifeng, Michael visits a women's mosque with a female imam, a delightful scene that ends with laughter and selfies! The Qing also undertook huge cultural enterprises. At a traditional printing house where the wood blocks are hand-carved, we see how the Complete Tang Poems were reproduced - all 48,000 of them. We travel through the wintry countryside to a remote village where a hardy audience watch open-air opera in the snow and visit a painter's studio, and 'storytelling' houses in Yangzhou. In the 18th century, China was arguably the greatest economy in the world, and we get a fabulous sense of the rich culture that came with prosperity. But then came the clash with the British, in the first Opium War, when a British expedition destroyed the Qing navy and extracted territory and trading rights. We leave with a glimpse of the future. 'Every dynasty has risen and declined,' says Michael, 'and has needed new life to regenerate, and this time the catalyst was the British.' Among the ports China ceded was an almost uninhabited island, Hong Kong, one of today's greatest financial centres, and Shanghai, a small town then but now one of the greatest cities in world.

Join investigators as they untangle the cause of Alzheimer’s and race to develop a cure. Alzheimer’s disease strikes at the core of what makes us human: our capacity to think, to love, and to remember. The disease ravages the minds of over 40 million victims worldwide, and it is one of the greatest medical mysteries of our time. Join investigators as they gather clues and attempt to reconstruct the molecular chain of events that ultimately leads to dementia". Follow key researchers in the field who have helped to develop the leading theories of the disease. Along the way, meet individuals from all walks of life who will reveal what it’s like to struggle with Alzheimer’s. Among them, members of a unique Colombian family who have learned that their genetic predisposition all but guarantees early onset Alzheimer’s. Yet there may be hope. Join these courageous patients participating in clinical trials, and then go behind the scenes of the major drug trials to see how researchers target and test therapies that may slow and even prevent Alzheimer’s