Embark on an astounding journey across 100,000 light-years to witness key moments in the history of the Milky Way. Using cutting-edge science, National Geographic constructs a 3-D state-of-the-art CGI model of our galaxy. We'll peer into the heart of the Milky Way on the hunt for super-massive black holes, watch how stars are born and die, fly out and above the plane of our galaxy to understand its true shape and scour its dusty spiral arms for the possibility of life

In the last episode, Iain discovers the remarkable impact of just one plant: grass. On the savannah of South Africa he sees how grass unleashed a firestorm to fight its greatest enemy, the forests. He shows how cutting your finger on a blade of grass shows us how it transformed life in the oceans. In Senegal, he meets the cleverest chimps in the world. And, in the ruins of the oldest temple on Earth, he tells the extraordinary story of how grass triggered human civilisation.

After eight grueling years of hunting in the hot, wind-scoured desert of central Africa, an international team of researchers has uncovered one of the most sensational fossil finds in living memory: the well-preserved 7 million years old skull of a chimp-size animal, probably a male, that doesn't fit any known species. According to paleontologist Michel Brunet of the University of Poitiers in France, whose team reported the find in Nature last week, there is no way it could have been an ape of any kind. It was almost certainly a hominid — a member of a subdivision of the primate family whose only living representative is modern man.

Dr. Hannah Fry takes us on a whistle-stop tour around the mathematics of success, to help us understand how to get more of what we want in our own lives. From the best way to bag a budget dinner or keep the kids quiet, to averting nuclear Armageddon and negotiating global climate change agreements.

From the detection of gravitational waves generated in space over a billion years ago, to discoveries in genetics here on Earth, we've collected the most compelling science breakthroughs and advances of 2016. Thanks to magnificent, hard-working scientists and researchers around the world, science keeps marching ever forward. And this year saw some discoveries that are absolutely brimming with the promise of greater discoveries, breakthroughs and quality of life in the future.

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.