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.

Join scientists as they grab light from across the universe to prove quantum entanglement is real. Einstein called it 'spooky action at a distance,' but today quantum entanglement is poised to revolutionize technology from computers to cryptography. Physicists have gradually become convinced that the phenomenon—two subatomic particles that mirror changes in each other instantaneously over any distance is real. But a few doubts remain.
The film follows a ground-breaking experiment in the Canary Islands to use quasars at opposite ends of the universe to once and for all settle remaining questions.

Time travel is not forbidden by the laws of nature, but to build a time machine, we would need to understand more about those laws and how to subvert them than we do now. And every day, science does learn more. In this film Horizon meets the scientists working on the cutting edge of discovery - men and women who may discover how to build wormholes, manipulate entangled photons or build fully functioning time crystals. In short, these scientists may enable an engineer of the future to do what we have so far been only able to imagine - to build a machine that allows us travel back and forward in time at the touch of a button. It could be you! Science fiction? Watch this film.

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.

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.

Diarmaid MacCulloch's own life story makes him a symbol of a distinctive feature about Western Christianity - scepticism, a tendency to doubt which has transformed both Western culture and Christianity. In the final programme in the series, he asks where that change came from. He challenges the simplistic notion that faith in Christianity has steadily ebbed away before the relentless advance of science, reason and progress, and shows instead how the tide of faith perversely flows back in. Despite the attacks of Newton, Voltaire, the French Revolutionaries and Darwin, Christianity has shown a remarkable resilience. The greatest damage to Christianity was actually inflicted to its moral credibility by the two great wars of the 20th century and by its entanglement with Fascism and Nazism. And yet it is during crisis that the Church has rediscovered deep and enduring truths about itself, which may even be a clue to its future.