The film covers the ever growing vegan movement and how it's best for the animals, human health, and the planet. It is the third instalment in a series of yearly movies documenting the global journey of veganism throughout the last 12 months. Vegan 2017 charts the movement's triumphs - as well as the adversity it has faced as it continues to grow. It is produced by Plant Based News Founder Klaus Mitchell.

In the last episode, Al-Khalili turns detective, hunting for clues that show how the scientific revolution that took place in the 16th and 17th centuries in Europe had its roots in the earlier world of medieval Islam. He travels across Iran, Syria and Egypt to discover the huge astronomical advances made by Islamic scholars through their obsession with accurate measurement and coherent and rigorous mathematics.He then visits Italy to see how those Islamic ideas permeated into the west and ultimately helped shape the works of the great European astronomer Copernicus, and investigates why science in the Islamic world appeared to go into decline after the 16th and 17th centuries, only for it to re-emerge in the present day. Al-Khalili ends his journey in the Royan Institute in the Iranian capital Tehran, looking at how science is now regarded in the Islamic world

Every day of our lives, we are bombarded by thousands of different images, images which affect us in countless different ways. But of all these there's one particular kind of image whose power is uniquely mesmerising, because while it terrifies us somehow it also comforts. But although it can manipulate us, it also reassures, It's the image of death.

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.

On the coast, two worlds collide. Coasts are the most dynamic and challenging habitats in the ocean - that brings great rewards but also great danger. The extraordinary animals that live here must find ingenious ways to cope with two very different worlds. This episode is a rollercoaster ride of heart-stopping action and epic drama, peopled with characters from the beautiful to the bizarre. We meet fish that live on dry land and puffins that must travel 60 miles or more for a single meal, and witness a life-and-death struggle in a technicolour rock pool. In a secluded cove in the Galapagos, sea lions feast on 60kg tuna. It should be impossible - tuna are usually far too fast for sea lions to catch. But here the sea lions club together to herd their prey inshore. Once trapped in the shallows, these huge fish are easy pickings. As the tide recedes in Brazil, lightfoot crabs leap from rock to rock, desperately avoiding the water - their lives depend on it. Moray eels launch themselves from rock pools, jaw gaping. Then octopuses, too. Both crawl across dry rock to set their ambush. Elsewhere, the ever-changing tides create rock pools. But these temporary worlds are a battleground. Predatory starfish turn a magical garden into the stuff of nightmares.

The years 1825-1918 were bloody and traumatic, a period when four tsars tried - and failed - to deal with the growing pressure for constitutional reform and revolution. In 1861, millions of enslaved serfs were freed by the Tsar-Liberator, Alexander II. But Alexander paid the ultimate penalty for opening the Pandora's box of reform when he was later blown up by terrorists on the streets of St Petersburg. Elsewhere, there was repression, denial, war and - in the case of the last tsar, Nicholas II - a fatalistic belief in the power of God, with Nicholas's faith in the notorious holy man Rasputin being a major part in his undoing. Lucy Worsley also details the chilling murder of Nicholas and his family in 1918, and asks whether all of this horror have been avoided.