Professor Marcus du Sautoy explores why we are driven to measure and quantify the world around us and why we have reduced the universe to just a handful of fundamental units of measurement. He tells the story of the metre and the second - how an astonishing journey across revolutionary France gave birth to the metre, and how scientists today are continuing to redefine the measurement of time and length, with extraordinary results.

Alice Roberts explores the latest discoveries in the study of human origins, revealing the transformation that has been brought about in this field by genetics. Traditional Palaeoanthropology, based on fossils, is being transformed by advanced genome sequencing techniques. We now know that there were at least four other distinct species of human on the planet at the same time as us - some of them identified from astonishingly well-preserved DNA extracted from 50,000-year-old bones, others hinted at by archaic sections of DNA hidden in our modern genome. What's more, we now know that our ancestors met and interacted with these other humans, in ways that still have ramifications today. Alice uses these revelations to update our picture of the human family tree.

Sir David Attenborough takes a breath-taking journey through the vast and diverse continent of Africa as it's never been seen before. From the richness of the Cape of Good Hope to blizzards in the high Atlas Mountains, from the brooding jungles of the Congo to the steaming swamps and misty savannahs, Africa explores the whole continent. An astonishing array of previously unknown places are revealed along with bizarre new creatures and extraordinary behaviours. Using the latest in filming technology including remote HD cameras, BBC One takes an animal's eye view of the action. The journey begins in the Kalahari, Africa's ancient southwest corner, where two extraordinary deserts sit side by side and even the most familiar of its creatures have developed ingenious survival techniques. Black rhinos reveal a lighter side to their character as they gather around a secret waterhole. Springbok celebrate the arrival of rains with a display of 'pronking'. Bull desert giraffes endure ferocious battles for territory in a dry river bed.

The film begins when journalist Craig Leeson, searching for the elusive blue whale, discovers plastic waste in what should be pristine ocean. In this adventure documentary, Craig teams up with free diver Tanya Streeter and an international team of scientists and researchers, and they travel to twenty locations around the world over the next four years to explore the fragile state of our oceans, uncover alarming truths about plastic pollution, and reveal working solutions that can be put into immediate effect.

It's a natural history epic. It's a compelling detective story. It's a scientific adventure at its best. It took Dr Fred Urquhart almost 40 years to discover the monarch butterflies' secret hideaway and prove the most incredible migration on Earth. Following the year-long annual migration cycle of the butterflies, the award-winning production team filmed hundreds of millions of monarchs in their remote overwintering sanctuaries in Mexico in 2011 and again in 2012 and also along their migratory routes from Canada, across the U.S. and into Mexico. The film immerses you in the astounding migration experience as two generations of the butterflies migrate north and then a Super Generation miraculously finds its way from Canada to a few isolated mountaintops in Mexico.

Japan's landscapes range from snowy mountains to subtropical warmth. They are full of wildlife - and animals' and people's lives often cross as they adapt to these extremes. The central island of Honshu is home to over 100 million people, and its biggest city, Tokyo, is one of the largest urban metropolises on earth. But it has a wild heart - most of Honshu is mountainous. This wilderness is home to an astonishing range of wildlife - black bears, monkeys, exquisite fireflies and even cow demons. But all across this island, from the mountains to the edge of the sea, people and nature are drawn together in the most unexpected ways.