Horizon follows the emotional journey of three young people with currently untreatable conditions to see if, within their lifetime, they can be cured.

In the past few years we have shivered through two record-breaking cold winters and parts of the country have experienced intense droughts and torrential floods. It is a pattern that appears to be playing out across the globe.

You might think that your memory is there to help you remember facts, such as birthdays or shopping lists. If so, you would be very wrong. The ability to travel back in time in your mind is, perhaps, your most remarkable ability, and develops over your lifespan.

lan Davies attempts to answer the proverbial question: how long is a piece of string? But what appears to be a simple task soon turns into a mind-bending voyage of discovery where nothing is as it seems.

Each year millions of people's lives are improved by the use of tissue from the dead. Bodies are used to supply spare parts, and for surgeons to practice on. Horizon investigates the medical revolution that has created an almost insatiable demand for body parts and uncovers the growing industry and grisly black market that supplies human bodies for a price.

Horizon plunges down the biggest rabbit-hole in history in search of the smallest thing in the universe.

Dr Kevin Fong finds out how doctors can avoid making mistakes in the high-pressure, high-stakes world of the operating theatre.

Time travel is not forbidden by the laws of nature, but to build a time machine, we would need to understand more about those laws and how to subvert them than we do now. And every day, science does learn more.

The quest to live longer has been one of humanities oldest dreams, but while scientists have been searching, a few isolated communities have stumbled across the answer. On the remote Japanese island of Okinawa, In the Californian town of Loma Linda and in the mountains of Sardinia people live longer than anywhere else on earth. In these unique communities a group of scientists have dedicated their lives to trying to uncover their secrets. Horizon takes a trip around the globe to meet the people who can show us all how to live longer, healthier lives.

We are bad at making decisions. According to science, our decisions are based on oversimplification, laziness and prejudice. And that's assuming that we haven't already been hijacked by our surroundings or led astray by our subconscious!

Dr Kevin Fong finds out how close scientists are to being able to mend your heart if it stops working. He meets some of the people who have undergone pioneering heart operations and the scientists who are pushing the limits of cardiac treatment.

Every day you make thousands of decisions, big and small, and behind all them is a powerful battle in your mind, pitting intuition against logic.Horizon uncovers the truth about how you really make decisions.

Is there any way to slow or even prevent the ravages of time? Veteran presenter Johnny Ball looks back over the 45 years that Horizon - and he - have been on air to find out what science has learned about how and why we grow old.

It's a macabre paradox, but almost every advance in aviation safety has been driven by a crash. After every crash, investigators determine its cause and scientists make every effort to ensure the same mistakes never happen again.

Twenty-five years after the world wide web was created, it is now caught in the greatest controversy of its existence - surveillance.

Recent research has analysed the link between the harmful effects of drugs relative to their current classification by law with some startling conclusions. Perhaps most startling of all is that alcohol, solvents and tobacco (all unclassified drugs) are rated more dangerous than ecstasy, 4-MTA and LSD (all class A drugs). If the current ABC system is retained, alcohol would be rated a class A drug and tobacco class B.

Dark flow is the latest in a long line of phenomena that have threatened to re-write the textbooks. Does it herald a new era of understanding, or does it simply mean that everything we know about the universe is wrong?

Horizon explores the strange and wonderful world of illusions - and reveals the tricks they play on our senses and why they fool us.

Dr Michael Mosley and Professor Alice Roberts investigate if male and female brains really are wired differently.

Professor Iain Stewart examines the powerful geological forces that unleashed the devastating Japanese earthquake, and explores how the release of this power of the planet brought Japan to the brink of a nuclear meltdown.

Jimmy Doherty, pig farmer, one-time scientist and poster-boy for sustainable food production is on a mission to find out if GM crops really can feed the world.

'To send a spacecraft there is a little bit insane,' says Scott Bolton when talking about Jupiter, the largest planet in the solar system. But that is exactly what he has done, because Scott is head of Juno, the Nasa mission designed to peer through Jupiter's swirling clouds and reveal the wonders within.

Horizon goes behind the scenes at Nasa to discover how it is preparing for its most ambitious and daring mission: to land men - and possibly women - on the surface of Mars.

The intriguing possibility of life on Mars has fuelled man's quest to visit the Red Planet. Drawing on 45 years of Horizon archive, space expert Dr Kevin Fong presents a documentary on Earth's near neighbour.

Transplant surgery has now reached incredible heights, from achieving full face transplants to growing organs in the lab. This Horizon Guide looks back at the extraordinary odds doctors and patients have had to overcome to achieve these amazing breakthroughs.

Dr Kevin Fong explores a medical revolution that promises to help us live longer, healthier lives. Inspired by the boom in health-related apps and gadgets, it's all about novel ways we can monitor ourselves around the clock. How we exercise, how we sleep, even how we sit.

A look at people living with OCD, the therapy available and what neuroscience can offer.

Science series. People like to think they are in control of their lives - of what they feel and think. But scientists are now discovering this is often simply an illusion.

Adam Rutherford meets a new creature created by American scientists - the spider-goat. It is part goat, part spider, and its milk can be used to create artificial spider\'s web.

Friendly bacteria, superfoods, cholesterol busting spreads, 99% germ free, whiter than white...it's almost impossible to find a product in the supermarket today that doesn't come with impressive claims, scientific claims with an inflated price tag to match. Are they oversold? Or are they worth the extra cash?