The planets of our solar system have experienced epic catastrophes throughout their long history, both raining down from outside and bubbling up from within. We'll voyage back in time to investigate the violent events that profoundly shaped the planets, including earth itself. We'll witness stunning revelations about what transformed Mars into a barren, hostile desert... The disaster that changed Venus from temperate to hellish... The impact that blew away Mercury's mantle, turning it into a planetary core... A colossal disturbance that rearranged the orbits of the gas giants... Titanic impacts on Jupiter... And how a lost moon may finally explain Saturn's rings.

Morgan Freeman narrates Island of Lemurs: Madagascar, the incredible true story of nature's greatest explorers - lemurs. Scientist Patricia Wright has a passion for preserving the life of one particular creature: the lemur. These lively animals found in Madagascar face all sorts of threats, just like so many other animals in a world in which they are increasingly crowded out by humans. Her passion for the subject is compelling and plainly evident, but it's the silent testimony of the animals themselves that really makes the case. Countless hours of footage are trimmed down to create this tapestry depicting the lives of these creatures of remarkable intelligence and ingenuity. Their daily routines and extraordinary adventures are awesome to behold, as is the way that the community functions. A full immersion into the world of the lemurs means great insights on these unusual animals.

This documentary tells the story a young polar bear's epic migration through the icy waters of Hudson Bay and his subsequent adventures on land, where he must spend the ice-free season. It is his first summer alone without his mother to guide and feed him. His struggle to survive is set against the biggest environmental story of our time: climate change. The stunning images were taken with more than eight different kinds of cameras including, for the first time, a polar bear collar-cam; a remote control Truck-cam; a mini Heli-cam, and several underwater cameras.

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.

Experts suspect that the dinosaurs were wiped out after a city-sized asteroid smashed into the Gulf of Mexico causing a huge crater. But until now, they haven't had any proof. In a world first, evolutionary biologist Ben Garrod joins a multi-million pound drilling expedition into the exact spot the asteroid hit to get hard evidence of the link. The team overcomes huge obstacles as it attempts to drill 1,500 metres beneath sea level to pull up rock from the Chicxulub crater. Meanwhile, paleopathologist Professor Alice Roberts travels the globe meeting top scientists and gaining exclusive access to a mass fossil graveyard in New Jersey - believed to date from the same time the asteroid hit. Alice also treks by horseback across the remote plains of Patagonia, to see if the effects of the asteroid impact could have wiped out dinosaurs across the world - almost immediately.

In the last episode, Iain discovers the remarkable impact of just one plant: grass. On the savannah of South Africa he sees how grass unleashed a firestorm to fight its greatest enemy, the forests. He shows how cutting your finger on a blade of grass shows us how it transformed life in the oceans. In Senegal, he meets the cleverest chimps in the world. And, in the ruins of the oldest temple on Earth, he tells the extraordinary story of how grass triggered human civilisation.