Changes to the bacteria that live inside all of us are responsible for increasing the number of people with allergies, suggests new research.

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.

It's the process that powers the Sun, and scientists know that if they could just make nuclear fusion happen here on Earth they could solve all the world's energy problems. Billions of dollars have been spent on trying to make it happen, but now an American scientist claims to have created nuclear fusion simply by bombarding a flask of liquid with sound waves. Many scientists refuse to believe his claims, so Horizon has assembled a team to replicate the experiment. This film reveals the team's findings

Michael Mosley puts himself through a battery of health tests available to people who feel perfectly well. From an expensive heart scan to a new national screening procedure to detect the earliest signs of bowel cancer, Mosley sets out to discover which if any of the tests are worth doing.

The search for extra-terrestrial life has been going for 50 years - but there's been a recent breakthrough. Astronomers have discovered a new planet called Gliese 581 c. It is the most Earth-like planet ever found. It orbits a star and may have habitats capable of supporting life. NASA hopes to find 50 more Earth-like planets by the end of the decade, all of which increases the chance that alien life has begun elsewhere.

Dr Alice Roberts asks one of the great questions about our species: are we still evolving? Alice follows a trail of clues from ancient human bones, to studies of remarkable people living in the most inhospitable parts of the planet, to the frontiers of genetic research to discover if we are still evolving - and where we might be heading.

What makes us good or evil? It's a simple but deeply unsettling question. One that scientists are now starting to answer.

Touch, sight, smell, hearing and taste - our senses link us to the outside world. Dr Kevin Fong looks back through 40 years of Horizon archives to find out what science has taught us about our tools of perception - why babies use touch more than any other sense, why our eyes are so easily tricked.

Professor Brian Cox takes a global journey in search of the energy source of the future. Called nuclear fusion, it is the process that fuels the sun and every other star in the universe. Yet despite over five decades of effort, scientists have been unable to get even a single watt of fusion electricity onto the grid.

In this third Horizon special, Dr Chris Van Tulleken is joined by his brother Xand and Dr Guddi Singh to take us through the latest developments and answer current concerns.

Forget the Big Bang. The real moment of creation was the moment of first light, the moment the first stars were born. Horizon tells the scientific version of the story of Genesis.

Horizon investigates a new era of Alzheimer's research, which is bringing hope to millions of sufferers across the world.

Scientists genuinely don't know what most of our universe is made of. The atoms we're made from only make up four per cent. The rest is dark matter and dark energy (for 'dark', read 'don't know'). The Large Hadron Collider at CERN has been upgraded. When it's switched on in March 2015, its collisions will have twice the energy they did before. The hope is that scientists will discover the identity of dark matter in the debris.

Scientists genuinely don't know what most of our universe is made of. The atoms we're made from only make up four per cent. The rest is dark matter and dark energy (for 'dark', read 'don't know'). The Large Hadron Collider at CERN has been upgraded. When it's switched on in March 2015, its collisions will have twice the energy they did before. The hope is that scientists will discover the identity of dark matter in the debris.

The film follows Rosemary, Phil and Ray as they undergo remarkable new treatments - from a billion pound genetically targeted drug designed to fight a type of skin cancer, to advanced robotic surgery.

Exploring the murky and fast-paced world of the hackers out to steal money and identities and wreak havoc with people's online lives, and the scientists who are joining forces to help defeat them.

The hunt for life within the long-dead bones of dinosaurs may sound like the stuff of Hollywood fantasy - but one woman has found traces of life within the fossilised bones of a T Rex.

Horizon reveals the science behind our perception of colour, a highly subjective illusion.

Earthquakes are among the most devastating natural disasters on the planet. In the last hundred years they have claimed the lives of over one million people. Earthquakes are destructive mainly because of their unpredictable nature. It is impossible to say accurately when a quake will strike but a new theory developed by Professor Geoffrey King could help save lives by preparing cities long in advance for an earthquake

The Ebola virus. No-one knows exactly where it comes from but one thing is certain - it\\\\\\\'s one of the most virulent infections known to science. This special episode of Horizon meets the scientists and doctors from all around the world looking for the cure and hears first-hand accounts of what it\\\\\\\'s actually like to catch - and survive - this terrible disease.

As Albert Einstein lay on his deathbed, he asked only for his glasses, his writing implements and his latest equations. He knew he was dying, yet he continued his work. In those final hours of his life, while fading in and out of consciousness, he was working on what he hoped would be his greatest work of all. It was a project of monumental complexity. It was a project that he hoped would unlock the mind of God.

Andrew Wiles stumbled across the world\'s greatest mathematical puzzle, Fermat\'s Theorem, as a ten- year-old schoolboy, beginning a 30-year quest with just one goal in mind - to solve the problem that has baffled minds for three centuries.

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.