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.

In the second episode, Professor Iain Stewart discovers how flowers have transformed our planet. He journeys to the remote islands of the South Pacific to track down the earliest flowers. In the deserts of Africa and rainforests of Vietnam, he sees how they brought brilliant colour to the most barren landscapes and sculpted the earth itself. And he learns how they drove the evolution of all animals - kick-starting our human story.

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.

A team of Australian and Chinese scientists discover mysterious ancient human remains from a remote cave in South West China. The bones are unlike any living human or any ancient human known to science, yet they were alive at the same time as humans of our own kind. Could they represent a new human species? And if so, what happened to these people?

Professor Jim Al-Khalili investigates the amazing science of gravity. A fundamental force of nature, gravity shapes our entire universe. It sculpts galaxies and warps space and time. But gravity’s strange powers also affect our daily lives in the most unexpected ways. This is a story with surprises in store for Jim himself. In telling the story of gravity, his own understanding of the nature of reality comes to be challenged. Finally, Jim discovers that, despite incredible progress, gravity still has many secrets to unveil.

Written and presented by David Attenborough, who said: 'One of the most wonderful things about filming plants is that you can reveal hidden aspects of their lives, you can capture the moment as one plant strangles another, and as they burst into flower. But whilst time-lapse photography allows you to see things that no human being has ever seen before". David begins his journey inside the magnificent Palm House, a unique global rainforest in London. Here, he explores the extraordinary plants that are so well adapted to wet and humid environments and unravels the intimate relationships between wet zone plants and the animals that depend on them. It was in the wet zones of the world that plants first moved on to land and in the Waterlily House David reveals how flowers first evolved some 140 million years ago. Watching a kaleidoscope of breath-taking time-lapses of these most primitive of flowers swelling and blooming in 3D, he is able to piece together the very first evolutionary steps that plants took to employ a wealth of insects to carry their precious pollen for the first time. David discovers clues to answer a question that even had Charles Darwin stumped: how did flowering plants evolve so fast to go on to colonise the entire planet so successfully?