What is the universe made of? If you answered stars, planets, gas and dust, you'd be dead wrong. Thirty years ago, scientists first realized that some unknown dark substance was affecting the way galaxies moved. Today, they think there must be five times our understanding of the universe and the nature of reality itself has drastically changed over the last 100 years - and it's on the verge of another seismic shift. In a 17-mile-long tunnel buried 570 feet beneath the Franco-Swiss border, the world's largest and most powerful atom smasher, the Large Hadron Collider, is powering up. Its goal is nothing less than recreating the first instants of creation, when the universe was unimaginably hot and long-extinct forms of matter sizzled and cooled into stars, planets, and ultimately, us. These incredibly small and exotic particles hold the keys to the greatest mysteries of the universe. What we find could validate our long-held theories about how the world works and what we are made of -- or, all of our notions about the essence of what is real will fall apart.

No planet beats Saturn for jaw-dropping beauty. Saturn is the most photogenic planet in all the solar system. Some of the pictures are to die for. But the postcards only tell part of the story. It really is rolling and seething inside. For ringside action, soar above the planet with its six-sided storms. Even more mystery surrounds the impressive Fountains of Enceladus where the secrets of life might spring from the moons salty geysers. And the samples are coming out in space, there's a big sign there: Free Samples: Take One.

Uranus and Neptune: The 'ice giants'. Strap yourselves in for an incredible voyage to the most remote and intriguing planets of all. There has never been a better time to boldly go where no human has gone before to follow in the footsteps of our robot pioneers and visit the planets of the Solar System. Ever wanted to be an astronaut? Imagine heading into the Ice Zone, the frigid, dark realm beyond the orbit of Saturn. So far from the Sun, you wouldn't expect much to be happening here. From orbit, Uranus appears sedate and calm. But why is the planet on its side? And Neptune: The second blue planet, and the last world in our Solar System. But something is driving its wild winds. And what about its Great Dark Spot? this planet just changes its spots. Leopards don't, but Neptune does.

Professor Brian Cox seeks to understand the nature of time and its role in creating both the universe and ourselves. From an extraordinary calendar built into the landscape of Peru to the beaches of Costa Rica, Brian explores the cycles of time which define our experience of life on Earth. But even the most epic cycles of life can't begin to compare to the vast expanse of cosmic time. Ultimately, Brian discovers that time is not characterised by repetition but by irreversible change. The vast universe is subject to these same laws of change. As we look out to the cosmos, we can see the story of its evolution unfold, from the death of the first stars to the birth of the youngest. This journey from birth to death will ultimately lead to the destruction not just of our planet, but also the entire universe, and with it the end of time itself. Yet without this inevitable destruction, the universe would be without what is perhaps the greatest wonder of all; the brief moment in time in which life can exist.

Professor Brian Cox takes on the story of the force that sculpts the entire universe - gravity. Gravity seems so familiar, and yet it is one of the strangest and most surprising forces in the universe. Starting with a zero gravity flight, Brian experiences the feeling of total weightlessness, and considers how much of an effect gravity has had on the world around us. But gravity also acts over much greater distances. It is the great orchestrator of the cosmos. It dictates our orbit around the sun, our relationship with the other planets in our solar system, and even the way in which our solar system orbits our galaxy. Yet the paradox of gravity is that it is actually a relatively weak force. Brian takes a face distorting trip in a centrifuge to explain how it is that gravity achieves its great power, before looking at the role it plays in one of the most extraordinary phenomena in the universe - a neutron star. Although it is just a few kilometres across, it is so dense that its gravity is 100, 000 million times as strong as on Earth. Over the centuries our quest to understand gravity has allowed us to understand some of the true wonders of the universe, and Brian reveals that it is scientists' continuing search for answers that inspires his own sense of wonder.

Our journey begins with David Attenborough at the North Pole, as the sun returns after six months of darkness. We follow a pair of courting polar bears, which reveal a surprisingly tender side. Next stop is the giant Greenland ice cap, where waterfalls plunge into the heart of the ice and a colossal iceberg carves into the sea. Humpback whales join the largest gathering of seabirds on earth to feast in rich Alaskan waters. Further south, the tree line marks the start of the Taiga forest, containing one third of all trees on earth. Here, 25 of the world's largest wolves take on formidable bison prey. At the other end of our planet, the Antarctic begins in the Southern Ocean where surfing penguins struggle to escape a hungry sea-lion and teams of orcas create giant waves to wash seals from ice floes -a filming first. Diving below the ice, we discover prehistoric giants, including terrifying sea spiders and woodlice the size of dinner plates. Above ground, crystal caverns ring the summit of Erebus, the most southerly volcano on earth. From here we retrace the routes of early explorers across the formidable Antarctic ice-cap - the largest expanse of ice on our planet. Finally, we rejoin David at the South Pole, exactly one hundred years after Amundsen then Scott were the first humans to stand there