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.

Push the limits of your imagination as astronomers attempt to grasp the mind-boggling extremes of size, distance and speed within our universe by bringing them down to earth. In this episode, our cast uses awesome analogies to bring the biggest objects, farthest distances and fastest speeds down to earth. To truly understand the scale of the cosmos, we jump behind the wheel of monster trucks, scale the Golden Gate Bridge, and race across the desert in a rocket-powered car.

The human eye is a remarkable piece of precision engineering, but it is also extremely limited. Beyond the narrow range of light that makes up the familiar colours of the rainbow is a vast spectrum of light, entirely unseen. Richard Hammond does just that, using ground-breaking new imaging technologies to take the viewer on a breath-taking journey of discovery beyond the visible spectrum, seeing the world, quite literally, in a whole new light. From death-defying aerial repairmen in the United States using ultraviolet cameras to seek out an invisible force that lurks unseen on power lines, to German scientists unlocking the secrets of animal locomotion with the world's most powerful moving x-ray camera, to infrared cameras that can finally reveal the secrets within a humble beehive, he shows how new technologies are letting us see our world anew.

This series shines a spotlight on the influential builders, dreamers and believers whose feats transformed the United States, a nation decaying from the inside after the Civil War, into the greatest economic and technological superpower the world had ever seen. The Men Who Built America is the story of a nation at the crossroads and of the people who catapulted it to prosperity. In the first episode, Cornelius Vanderbilt grows from a steamboat entrepreneur to the head of a railroad empire, and gets into a heated rivalry with Jim Fisk and Jay Gould; the up and coming John D. Rockefeller founds Standard Oil. Many business owners lay their own rail lines which leads to the Panic of 1873. Later, Rockefeller starts to expand his wealth by diverting his business from the railroads to a new innovation, oil pipelines.

In this series Professor Iain Stewart tells a stunning new story about our planet. He reveals how the greatest changes to the Earth have been driven, above all, by plants. In this first episode Iain journeys from the spectacular caves of Vietnam to the remote deserts of Africa. He sees how plants first harnessed light from the sun and created our life-giving atmosphere. He uncovers the epic battle between the dinosaurs and the tallest trees on the planet. And, using remarkable imagery, he shows plants breathing - and for the first time talking to each other.

J.P. Morgan proceeds to banish the dark with the direct current electric light of Thomas Edison, but the two soon face serious competition from the alternating current of George Westinghouse and Nikola Tesla. As the 19th century comes to a close, the titans of industry must try to work together to stop a new threat in budding politician William Jennings Bryan, who threatens to dissolve monopolies in America.