This episode examines those birds whose sustenance comes from flesh and their methods of hunting. In New Zealand, Sir Attenborough observes Keas, parrots that do not eat meat exclusively, raiding a shearwater's burrow for a chick. However, it is the dedicated birds of prey, such as owls, buzzards, eagles, falcons and vultures, to which much of the programme is devoted. In order to spot and pursue their victims, senses of sight and hearing are very acute. Vultures are the exception, in that they eat what others have left, and once a carcass is found, so many birds descend on it that the carrion seems submerged beneath them. The Turkey Vulture is an anomaly within its group, as it also has a keen sense of smell. Eagles defend their territory vigorously, and a pair of sea eagles are shown engaging in an aerial battle. The Galápagos Hawk hunts Marine Iguanas, but can only do so when its quarry is vulnerable, during the breeding season. The African Harrier Hawk has adapted to extracting burrowing animals by virtue of an especially long, double-jointed pair of legs. By contrast, a shrike is not equipped with the requisite sharp beak and talons needed for butchery, and so dismembers its kill by impaling it on the thorns of acacias. The Lammergeier eats bones, and will drop them on to rocks from a great height in order to break them down to a digestible size. Also featured are the Eurasian Sparrowhawk, Goshawk and Peregrine Falcon.

When ancient Greece fell into decline, mathematical progress stagnated as Europe entered the Dark Ages, but in the East mathematics reached new heights. In the second episode, Du Sautoy explores how maths helped build imperial China and discovers how the symbol for the number zero was invented in India. He also looks at the Middle Eastern invention of algebra and how mathematicians such as Fibonacci spread Eastern knowledge to the West.

Carl Sagan teaches students in a classroom in his childhood home in Brooklyn, New York, which leads into a history of the different mythologies about stars and the gradual revelation of their true nature. In ancient Greece, some philosophers (Aristarchus of Samos, Thales of Miletus, Anaximander, Theodorus of Samos, Empedocles, Democritus) freely pursue scientific knowledge, while others (Plato, Aristotle, and the Pythagoreans) advocate slavery and epistemic secrecy.

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.

This documentary series charting the visual appeal and historical meaning of maps. The Hereford Mappa Mundi, the largest intact Medieval wall map in the world, its ambition to picture all of human knowledge in a single image is breathtaking. The work of a team of artists, the world it portrays is overflowing with life, featuring Classical and Biblical history, contemporary buildings and events, animals and plants from across the globe, and the infamous 'monstrous races' which were believed to inhabit the remotest corners of the Earth.

There is no greater test for life than winter, as temperatures plummet to 70 below and winds reach 200kph. Darkness and ice extend across the polar regions and only a few remarkable survivors gamble on remaining. We join a female polar bear trekking into the Arctic mountains to give birth as the first blizzards arrive. Out on the frozen ocean, the entire world's population of spectacled eider ducks brave the winter in a giant ice hole kept open by ferocious currents. Arctic forests transform into a wonderland of frost and snow - the scene of a desperate and bloody battle between wolf and bison, but also where a remarkable alliance between raven and wolverine is made. Beneath the snow lies a magical world of winter survivors. Here tiny voles dodge the clutches of the great grey owl, but cannot escape the ultimate under-show predator - the least weasel. Midwinter and a male polar bear wanders alone across the dark, empty icescape. Below the snow, polar bear cubs begin life in an icy den while fantastical auroras light the night skies above. In Antarctica, we join male emperor penguins in their darkest hour, battling to protect precious eggs from fierce polar storms. Weddell seals escape to a hidden world of jewel-coloured corals and alien-looking creatures but frozen devastation follows as sinister ice stalactites reach down with deadly effect.