The Pythagorean Theorem is simple: x2 + y2 = z2. In this form, the equation can be solved. But what if the 2 is replaced with any positive integer greater than 2? Would the equation still be solvable? More than 300 years ago, amateur mathematician Pierre de Fermat said no, and claimed he could prove it. Unfortunately, the book margin in which he left this prophecy was too small to contain his thinking. Fermat's Last Theorem has since baffled mathematicians armed with the most advanced calculators and computers. Andrew Wiles methodically worked in near isolation to determine the proof for this seemingly simple equation.

Where did we come from? What makes us human? Groundbreaking investigation explores how new discoveries are transforming views of our earliest ancestors. Featuring interviews with world-renowned scientists, footage shot in the trenches as fossils were unearthed, and stunning computer-generated animation, Becoming Human brings early hominids to life, examining how they lived and how we became the creative and adaptable modern humans of today. In the first episode Selam, the amazingly complete remains of a 3 million year-old child, packed with clues to why we split from the apes, came down from the trees, and started walking upright.

A major new series exploring the wildlife of South America. This is a breathtaking aerial journey through the most spectacular locations on the continent, from the icy peaks of the Andes to the Amazon jungle and the Atacama desert. These extreme conditions are home to a mind-boggling variety of creatures, many of them rarely seen before on television.

For centuries scientists have been attempting to come up with an elixir of youth. Now remarkable discoveries are suggesting that ageing is something flexible that can ultimately be manipulated. The scientists are attempting to piece together why we age and more vitally for all of us, what we can do to prevent it. But which theory will prevail? Does the real key to controlling how we age lie with a five-year-old boy with an extraordinary ageing disease or with a self-experimenting Harvard professor? Could one of these breakthroughs really see our lives extend past 120 years?

We are in the grip of an allergy epidemic. 50 years ago one in 30 were affected, but in Britain today it is closer to one in three. Why this should be is one of modern medicine's greatest puzzles. In search of answers, Horizon travels round the globe, from the remotest inhabited island to the polluted centres of California and the UK. We meet sufferers and the scientists who have dedicated their lives trying to answer the mystery of why we are becoming allergic to our world.

It's 3.5 million years ago and in East Africa a remarkable species of ape roams the land. Australopithecus afarensis has taken the first tentative steps towards humanity by standing and walking on two legs. The rift valley was forming, and the rain forests dying as Africa dried out - turning the landscape into a mosaic of scattered trees and grass. In this new environment afarensis found it more efficient to move about on two legs rather than four.