Documentary AreaSimply the best Documentaries

Carl Sagan teaches students in a classroom in his childhood home in Brooklyn, New York, which leads into a history of the different mythologies about stars and the gradual revelation of their true nature. In ancient Greece, some philosophers (Aristarchus of Samos, Thales of Miletus, Anaximander, Theodorus of Samos, Empedocles, Democritus) freely pursue scientific knowledge, while others (Plato, Aristotle, and the Pythagoreans) advocate slavery and epistemic secrecy.

In the fourth episode of the series, Clovis was the first Frankish king to acknowledge the Christian faith. This changed the direction of Europe's history.

The final part reveals how our knowledge of cells has brought us to the brink of one of the most important moments in history. Scientists are close to repeating what has happened only once in four billion years - the creation of a new life form.

There is no greater test for life than winter, as temperatures plummet to 70 below and winds reach 200kph. Darkness and ice extend across the polar regions and only a few remarkable survivors gamble on remaining. We join a female polar bear trekking into the Arctic mountains to give birth as the first blizzards arrive. Out on the frozen ocean, the entire world's population of spectacled eider ducks brave the winter in a giant ice hole kept open by ferocious currents. Arctic forests transform into a wonderland of frost and snow - the scene of a desperate and bloody battle between wolf and bison, but also where a remarkable alliance between raven and wolverine is made. Beneath the snow lies a magical world of winter survivors. Here tiny voles dodge the clutches of the great grey owl, but cannot escape the ultimate under-show predator - the least weasel. Midwinter and a male polar bear wanders alone across the dark, empty icescape. Below the snow, polar bear cubs begin life in an icy den while fantastical auroras light the night skies above. In Antarctica, we join male emperor penguins in their darkest hour, battling to protect precious eggs from fierce polar storms. Weddell seals escape to a hidden world of jewel-coloured corals and alien-looking creatures but frozen devastation follows as sinister ice stalactites reach down with deadly effect.

The tour was designed by Willie Williams, who has worked on every U2 tour since 1982. Williams had been toying with ideas for 360-degree stadium staging for U2 for a number of years, and presented sketches of a four-legged design to the group near the end of their Vertigo Tour in 2006. The inspiration for the 'spaceship-on-four-legs' design, nicknamed 'the Claw', came from the landmark Theme Building at Los Angeles International Airport.

The 25 October 2009 concert in Pasadena, California was streamed live on U2's YouTube channel, the first time a concert was streamed live on YouTube. Over 10 million viewers streamed the concert, making it the largest streaming event in the website's history. The shoot was directed by Tom Krueger, who had previously worked with the band on the film U2 3D.