Here, Aleks charts how the Web is forging a new brand of politics, both in democracies and authoritarian regimes. With contributions from Al Gore, Martha Lane Fox, Stephen Fry and Bill Gates, Aleks explores how interactive, unmediated sites like Twitter and YouTube have encouraged direct action and politicised young people in unprecedented numbers. Yet, at the same time, the Web's openness enables hardline states to spy and censor, and extremists to threaten with networks of hate and crippling cyber attacks.

We think of comets as beautiful glowing balls of light streaking across our skies with their long sweeping tails, yet comets are so much more than just a cosmic firework display. Comets have a uniquely important place in modern science. As time machines from the early universe, they could hold the key to unlock the secrets of the cosmos. Comets could even be the origin of life itself. We follow the incredible odyssey of a comet as it sails through the solar system, watching it's every move as it evolves from a dormant chunk of ice and rock into a tumbling, violently active nucleus engulfed in a gaseous haze. What we learn is a revelation; comets are even more mysterious and fascinating than we had ever imagined.

'Dinosaurs: Giants of Patagonia' Following Pr Rodolfo Coria, a world-reknown Argentinian paleontologist, we visit sites of major discoveries he has contributed to in Patagonia and travel back in time to see these amazing beasts come to life in 3D. Patagonia has given us the largest living animal to ever walk the Earth: the titanesque plant-eating Argentinosaur, and its nemesis, the Giganotosaur, a bipedal carnivore that could easily challenge the famous T-Rex.

David Attenborough discovers the plants that have evolved to shed their dependency on water enabling them to survive in the driest environments. The story begins at midnight in midsummer as David steps into the Princess of Wales Conservatory to witness the extraordinary nocturnal blooming of a cactus. The queen of the night, with its giant flowers, is the centre piece of a stunning symphony of cacti blooms that burst open in the desert (and at Kew) at night. In a mesmerizing 3D slow motion sequence, we discover the extraordinary connections between cacti and their natural pollinators: bats. As the sun rises, David meets other amazing plants. Species like the century plant, the Agave franzosini, which grows steadily for over 50 years, only to then flower itself to death with one mighty telegraph pole sized bloom which literally bursts out of the roof of Kew’s green house.

This episode tells the tale of what's broadly considered China's most creative dynasty - the Song (960-1279). Michael Wood heads to the city of Kaifeng, the greatest city in the world before the 19th century. Here in Twin Dragon Alley, locals tell him the legend of the baby boys who became emperors.
He explores the ideas and inventions that made the Song one of greatest eras in world culture, helped by China's most famous work of art, the Kaifeng scroll, which shows the life of the city in around 1120. A chef makes Michael a recipe from a Song cookbook, while a guide to 'how to live happy, healthy lives for old people', published in 1085 and still in print, is discussed with local women doing their morning exercises. The Song was also a great era for scientific advance in China. Michael steers a huge working replica of an astronomical clock, made by China's Leonardo da Vinci.
Then at a crunch Chinese Premier League match, Michael tells us the Chinese invented football! The golden age of the northern Song ended in 1127, when invaders sacked Kaifeng, but they survived in the south. At their new capital, Hangzhou, Wood joins locals dancing by the West Lake, while in the countryside he meets Mr Xie with his records of 40 generations of ancestors. The final defeat of the Song took place in a naval battle in the estuary of the Pearl River in 1279. When all was lost, rather than surrender to the Mongols, a loyal minister jumped into the sea with the young boy emperor in his arms. 'So ended the glory of the Song', Wood concludes, 'but a new age would arise... as in China, it always has!'.

We are the most power-hungry generation that has ever lived. This film tells the story of how that power has been harnessed - from wind, steam and from inside the atom. In the early years the drive for new sources of power was led by practical men who wanted to make money. Their inventions and ideas created fortunes and changed the course of history, but it took centuries for science to catch up, to explain what power is, rather than simply what it does. This search revealed fundamental laws of nature which apply across the universe, including the most famous equation in all of science, e=mc2.