The second episode is about how plants gain their sustenance. Sunlight is one of the essential requirements if a seed is to germinate, and Attenborough highlights the cheese plant as an example whose young shoots head for the nearest tree trunk and then climb to the top of the forest canopy, developing its leaves en route. Using sunshine, air, water and a few minerals, the leaves are, in effect, the "factories" that produce food. However, some, such as the begonia, can thrive without much light. To gain moisture, plants typically use their roots to probe underground. Trees pump water up pipes that run inside their trunks, and Attenborough observes that a sycamore can do this at the rate of 450 litres an hour — in total silence. Too much rainfall can clog up a leaf's pores, and many have specially designed 'gutters' to cope with it. However, their biggest threat is from animals, and some require extreme methods of defence, such as spines, camouflage, or poison. Some can move quickly to deter predators: the mimosa can fold its leaves instantly when touched, and the Venus flytrap eats insects by closing its leaves around its prey when triggered. Another carnivorous plant is the trumpet pitcher that snares insects when they fall into its tubular leaves. Attenborough visits Borneo to see the largest pitcher of them all, Nepenthes rajah, whose traps contain up to two litres of water and have been known to kill small rodents.

In the center of the story is the life of the indigenous people of the village Bakhtia at the river Yenisei in the Siberian Taiga. The camera follows the protagonists in the village over a period of a year. The natives, whose daily routines have barely changed over the last centuries, keep living their lives according to their own cultural traditions. Werner Herzog and Russian co-director Dmitry Vasyukov takes viewers on yet another unforgettable journey into remote and extreme natural landscapes. The acclaimed filmmaker presents this visually stunning documentary about indigenous people living in the heart of the Siberian Taiga. Deep in the wilderness, far away from civilization, 300 people inhabit the small village of Bakhtia at the river Yenisei. There are only two ways to reach this outpost: by helicopter or boat. There's no telephone, running water or medical aid. Follow the Siberian trappers through all four seasons of the year to tell the story of a culture virtually untouched by modernity.

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.

There's evidence that dark matter makes up 85% of all the matter in the universe. We can see dark matter holding galaxies together and ripping other structures apart, we even see it bending light. Dark matter itself has been around since the beginning of the universe. Without dark matter, we wouldn't be here. But if you can't see dark matter and if you can't touch it, does it really exist?
Dark Matter is thought to be the cosmic glue that holds the universe together, yet the search for it continues to eluded scientists today.

An intimate and heart-warming look at the man behind the legend - as we've never seen Ali before. Told through exclusive, unprecedented access to Ali's personal archive of 'audio journals' combined with touching interviews and testimonials from his inner circle of family and friends, including his daughters, son, brother and former wife, plus legends of the boxing community including Mike Tyson, George Foreman and Gene Kilroy

When we look up into the sky it appears we live in a universe that is filled with light. But scientists are now certain there is far more matter in the dark portions of our universe that we can’t see or touch. There’s something hiding in the shadows. Cosmologists agree that 'dark matter' has helped shape our Universe, but now they need to figure out what dark matter is. What’s going on in this hidden world? Could it have formed its own dark stars, planets, and even life forms? Could this Shadow Universe threaten our world of light?