We can survive for weeks without food, but only days without water: it is the essential element of life. Yet many millions of us live in parched deserts around the world. In the second episode of Human Planet, we discover how the eternal quest for water brings huge challenges - and ingenious solutions - in the driest places on Earth. Battling through a sand storm in Mali, Mamadou must get his cows to a remote lake but desert elephants have arrived first. Can he find a safe way through the elephant blockade? Alone for weeks on end, Tubu women and children navigate the endless dunes of the Sahara. How does young Shede know where to find the last oasis, three days walk across the sea of sand? At the height of the drought we witness a spectacular frenzy: two thousand men rushing into Antogo Lake to catch the fish trapped by the evaporating water. When the rain finally arrives in the desert it's a time for flowering and jubilation - and love. The Wodaabe men of Niger put on make-up for an intoxicating courtship dance and beauty contest.

Einstein's world-shaking Theory of Relativity says that time travel is perfectly possible -- if you're going forward in time. Finding a way to travel backwards requires breaking the speed of light, which so far seems impossible. But now, strange-but-true phenomena such as quantum nonlocality (where particles instantly teleport across vast distances) may give us a way to make the dream of traveling back and forth through time a reality. Step into a time machine and rewrite history, bring loved ones back to life, control our destinies. But if succeed, what are the consequences of such freedom? Will we get trapped in a plethora of paradoxes and multiple universes that will destroy the fabric of the universe?

Spy in the Huddle use innovative techniques to reveal the incredible secrets of your pets' behaviour in ways never seen before. As astonishing photography explores the wild side of our playful pets, find out why hamsters love to run in a wheel, how dogs pick up the rules of the pack and how kittens learn to be solitary hunters. Featuring incredible views of plunge-diving dogs, babysitting cats, acrobatic hamsters and a playful cat outwitted by his prey" - you'll never look at your favourite companions in quite the same way again. The latest science also reveals why budgies talk, how a cat scales a vertical wall with the help of a special claw, why hamsters stuff their faces with more food than they can eat and the real meaning behind a rabbit's hop. Our pets are also given a chance to explore their wild side as we join the free-roaming pet dogs of Cusco Peru, pet rabbits living in a natural warren and the wild-living inhabitants of Cat Island, Japan. A range of innovative techniques such as moving X-rays, thermal imagery, minicam-carrying dogs and revelatory slow-motion photography shows why our pets play and how their true wild nature is just a whisker away.

Join investigators as they untangle the cause of Alzheimer’s and race to develop a cure. Alzheimer’s disease strikes at the core of what makes us human: our capacity to think, to love, and to remember. The disease ravages the minds of over 40 million victims worldwide, and it is one of the greatest medical mysteries of our time. Join investigators as they gather clues and attempt to reconstruct the molecular chain of events that ultimately leads to dementia". Follow key researchers in the field who have helped to develop the leading theories of the disease. Along the way, meet individuals from all walks of life who will reveal what it’s like to struggle with Alzheimer’s. Among them, members of a unique Colombian family who have learned that their genetic predisposition all but guarantees early onset Alzheimer’s. Yet there may be hope. Join these courageous patients participating in clinical trials, and then go behind the scenes of the major drug trials to see how researchers target and test therapies that may slow and even prevent Alzheimer’s

Above all, 'In Search of Beethoven' addresses the central myth of Beethoven's life and work -- that of the heroic, tormented figure battling to overcome the tragic fate of being struck down by deafness in his prime; a man who searched for his elusive, eternal 'immortal beloved,' yet was never to attain lasting happiness.

Rocky Braat went to India as a disillusioned tourist. When he met a group of children with AIDS, he decided to stay. He never could have imagined the obstacles he would face, or the love he would find.