Ancient Greece's most powerful god wages an epic struggle against his father for control of the universe. It's the ultimate Clash of the Gods as the Olympians challenge the Titans in mythology's greatest showdown. This is a pivotal battle that experts believe may have been ancient code for a real world event - one of the greatest natural disasters the Earth ever experienced.

Right now cosmic forces prowl the universe and threaten man's very existence. They're asteroids and comets; they've left their imprint on planet Earth, literally. Initially helping to build planets through violent collisions, during this fiery bombardment period they may have even seeded Earth with water and the building blocks for life. Since the turbulent formation of the solar system, these space rocks have continued to impact Earth. Some have been so violent that they've led to mass extinctions, including one that wiped out the dinosaur. New theories suggest that asteroid and comet dust harbour deadly viruses that may have triggered some of our worst pandemics. The possibility of future collisions remains a legitimate threat yet despite their dangers, asteroids and comets may hold vital natural resources, which could actually preserve

A variety of cosmic events have both helpful and harmful effects on life on Earth. From the beauty of the Aurora Borealis and rainbows to the dangers of UV radiation and cosmic rays, from the miracle of photosynthesis to the thrill of a meteor shower, this episode explores how the effects generated by the sun and other extra-solar sources can literally get under our skin, scramble our technology, make life possible and threaten our existence all at the same time

From east to west, via mountains, volcanoes, deserts, lakes and Arctic ice, this breathtaking series uses stunning cinematography to chart the dazzling natural wonders of this vast country. Accounting for around 10 per cent of the world’s dry land, Siberia is famous as a brutally cold place. Yet it is home to a diverse range of habitats and animal life – including musk deer, camels, gazelles and the extraordinary Siberian salamander, which can spend years encased in -40°C ice and still survive.

Documentary which tells the story of the theory of evolution by natural selection which is now scientific orthodoxy, but when it was unveiled it caused a storm of controversy. Many people criticised it for being short on evidence and long on assertion and Darwin, being the honest scientist that he was, agreed with them. He entrusted future generations to complete his work and prove the essential truth of his vision. Evolutionary biologist Professor Armand Marie Leroi argues that, with the new science of evolutionary developmental biology (evo devo), it may be possible to take that theory to a new level - to do more than explain what has evolved in the past, and start to predict what might evolve in the future.

Cannabis is the world's favourite drug, but also one of the least understood. Can cannabis cause schizophrenia? Is it addictive? Can it lead you on to harder drugs? Or is it simply a herb, an undervalued medicine? Addiction specialist Dr John Marsden discovers that modern science is finally beginning to find answers to these questions. John traces the cannabis plants' birthplace in Kazakhstan; finds the origins of our sensitivity to cannabis in the simple sea squirt; and finds out just what it does to our brains. He meets people who have been changed by this drug in drastically different ways - from those whose lives have been shattered to those who lives have been revived.