In 1799, the German scientist Alexander von Humboldt embarked on a perilous journey of discovery across South America. It would take him to the deepest jungle near the Orinoco and to the heights of the Andes. His aim was twofold: to conduct the first scientific survey of South America and to discover how the natural world actually works — at a time when most scientists believed that the world was created less than 6,000 years ago. He later became a leading scientific figure and champion of the abolitionist movement in the US.
This extremely visual docudrama follows Humboldt’s extraordinary path. Travelling in Humboldt’s footsteps is historian Andrea Wulf, whose book on Humboldt became a worldwide bestseller. For good reason, since Humboldt’s ideas on the planet’s fragile web of life are as important today as they were 220 years ago.

The hunt for aliens is on! After a distinguished career in cosmology Professor Martin Rees, the astronomer royal, has taken up the search for extra-terrestrials. Looking for aliens is no longer science fiction - it is a question that's engaging some of the greatest minds in science." As our knowledge of the universe has increased, we're getting closer to answers. Many scientists now think we live in galaxy with a billion Earth-like planets, many of which may be teeming with life. But what kind of life? Has anything evolved into beings we could communicate with? This film gets inside the minds of the scientists considering one of the most exciting and profound questions we can ask - are we alone in the universe? Professor Rees thinks we may have our idea of what an alien is like all wrong. If he's right, it's not organic extra-terrestrials we should look for, it's machines.

Physicist Dr Helen Czerski journeys to the extremes of the temperature scale, where the everyday laws of physics break down and a new world of scientific possibilities begins. In the first part, Frozen Solid, Helen reveals how cold has shaped the world around us and why frozen doesn't mean what you think it does. She meets scientists pushing temperature to the limits of cold, driving technologies such as superconductors.
The second part, A Temperature for Life, explores the narrow band of temperature that has led to life on Earth, how life began where hot meets cold and how every living creature depends on temperature for survival. In the last part, Playing with Fire, Helen Czerski explores the science of heat. She reveals how heat is the hidden energy contained within matter with the power to transform it from state to state.

This documentary tells the story a young polar bear's epic migration through the icy waters of Hudson Bay and his subsequent adventures on land, where he must spend the ice-free season. It is his first summer alone without his mother to guide and feed him. His struggle to survive is set against the biggest environmental story of our time: climate change. The stunning images were taken with more than eight different kinds of cameras including, for the first time, a polar bear collar-cam; a remote control Truck-cam; a mini Heli-cam, and several underwater cameras.

Welcome to an extreme landscape of rock, ice and snow. We tour the mightiest mountain ranges, starting with the birth of a mountain at one of the lowest places on Earth and ending at the summit of Everest. Find out how some of the most secretive animals rise to the challenge of mountain life. Share one of Earth's rarest phenomena, a lava lake that has been erupting for over 100 years. The same forces built the Simian Mountains where we find troops of gelada baboons nearly a thousand strong. In the Rockies, grizzlies build winter dens inside avalanche-prone slopes and climb the peaks to devour abundant summer moths. In another world first, the programme brings us astounding images of a snow leopard hunting on the Pakistan peaks.

Horizon investigates the idea that the best way to lose weight successfully is a personalised approach, diets tailored to our individual biology and psychology. In a groundbreaking experiment, Dr Chris van Tulleken and Tanya Byron join a team of experts to put 75 overweight volunteers on diets designed to tackle the specific reasons why they eat too much. The volunteers are put through a series of tests at a residential clinic to understand how their genes, hormones and psychology influence their eating behaviour. They are then put on the diets the experts believe are best suited to them. Can science succeed where other diets have failed?