The plains of Africa, home to a powerful predator where females rule: spotted hyena. They have a reputation as dim-witted scavengers. But these fierce queens are the opposite; strong, fearless and highly intelligent. Hyenas are the girl gang of the Savannah. They hunt in packs, get first bite of their prey, and outrank every male in their group, making them some of Africa's most fierce queens.

Professor Jim Al-Khalili investigates the amazing science of gravity. A fundamental force of nature, gravity shapes our entire universe. It sculpts galaxies and warps space and time. But gravity’s strange powers also affect our daily lives in the most unexpected ways. This is a story with surprises in store for Jim himself. In telling the story of gravity, his own understanding of the nature of reality comes to be challenged. Finally, Jim discovers that, despite incredible progress, gravity still has many secrets to unveil.

In the days of the Mayas, cenotes – deep, natural pits on the Yucatan peninsula - provided the only means of obtaining drinking water. But in the mythology of this advanced civilisation, these waterholes and caves were also the entrance to Xibalba – the underworld. All deceased were obliged to pass through Xibalba and wait there until they were called into heaven. It was a place in which one made sacrifices to the gods – objects of daily life, as well as bloody, human sacrifices. To this day, the relics of these acts are still in place preserved underwater for more than a thousand years. The entrance to the underworld begins at a dirty waterhole in the middle of the Mexican jungle overgrown and barely recognisable. But immediately after entry, a hall of breath-taking dimensions and beauty is revealed. As if they were sculptures, stalactites and stalagmites lend the underwater cave an almost sacred ambience. By now, one has succumbed to the fascination emanated by the world’s largest underwater cave system. We accompany four professional research divers to Yucatan – a team of specialists, able to squeeze their bodies through crevices and holes, barely larger than their bodies and who master dives that would push even the most experienced divers to their limits. With them, we penetrate worlds only a few people have ever ventured into. We encounter the remains of human victims, prehistoric fireplaces and primeval animal skeletons and undertake a dive, which takes us from the primeval forest to the open sea. We then enter Xibalba – the place of myths and the dead. In the days of the Mayas - a voyage of no return. Today, this is one of the greatest challenges one can face as a diver – the hidden world of the underwater caves of Yucatan – all filmed in 3D.

Andrew Marr sets off on an epic journey through 70,000 years of human history. Using dramatic reconstructions, documentary filming around the world and cutting-edge computer graphics, he reveals the decisive moments that shaped the world we live in today, telling stories we thought we knew and others we were never told." Starting with our earliest beginnings in Africa, Marr traces the story of our nomadic ancestors as they spread out around the world and settled down to become the first farmers and townspeople. He uncovers extraordinary hand-prints left in European caves nearly 30,000 years ago and shows how human ingenuity led to inventions which are still with us today. He also discovers how the first civilisations were driven to extremes to try to overcome the forces of nature, adapting and surviving against the odds, and reveals how everyday life in ancient Egypt had more in common with today's soap operas than might be imagined.

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.

In the Land of the Cave Bear, Alice ventures to the parts of the northern hemisphere, hit hardest by the cold - Europe and Siberia. High in the mountains of Transylvania, a cave sealed for thousands of years reveals grisly evidence for a fight to the death between two staving giants, a cave bear and a cave lion. Yet Alice discovers that for woolly rhinos and woolly mammoths, the Ice Age created a bounty. The Mammoth Steppe, a vast tract of land which went half way round the world, provided food all year round, for those that liked the cold. It was these mammoths that Europe's most dangerous predators hunted for their survival.