Medusa was the most infamous female fiend in Greek mythology, whose look turned every living thing to stone. But what is the true story behind the snake-haired gorgon? Find out about this evil Gorgon's real world connection to human corpses and learn what clues the night sky holds concerning the origins of the tale of Medusa.

More than 2,000 years ago, the thriving city of Petra rose up in the bone-dry desert of what is now Jordan. An oasis of culture and abundance, the city was built by wealthy merchants whose camel caravans transported incense and spices from the Arabian Gulf. They carved spectacular temple-tombs into its soaring cliffs, raised a monumental Great Temple at its heart, and devised an ingenious system that channeled water to vineyards, bathhouses, fountains, and pools. But following a catastrophic earthquake and a slump in its desert trade routes, Petra's unique culture faded and was lost to most of the world for nearly a thousand years. Now, in a daring experiment, an archaeologist and sculptors team up to carve an iconic temple-tomb to find out how the ancient people of Petra built their city of stone. Meanwhile, scientists using remote sensors and hydraulic flumes uncover the vast city and its sophisticated water system. The race is on to discover how these nomads created this oasis of culture in one of the harshest climates on Earth.

The final leg takes him from the Khyber Pass through Pakistan to the Punjab, where Alexander's army mutinied and he was forced to return across the Makran Desert to Babylon, where he died at only 32 years of age.

Journey through the long-vanished corners of prehistoric North America, beginning when man first entered the vast, unspoiled continent some 14,000 years ago, in this appealing BBC documentary. Witness ancient beasts, mammoths, mastodons, giant bears, and sabre-toothed cats, and see the legacies each has passed to their modern successors. Computer animation and digital effects bring to life mammoths, saber-toothed cats, giant ground sloths, short-faced bears, glyptodonts, and a plethora of smaller animals in a lush Ice Age mosaic.

Michael Mosley has set himself a truly ambitious goal: he wants to live longer, stay younger and lose weight in the bargain. And he wants to make as few changes to his life as possible along the way. He discovers the powerful new science behind the ancient idea of fasting, and he thinks he's found a way of doing it that still allows him to enjoy his food. Michael tests out the science of fasting on himself - with life-changing results.

Dr Alice Roberts asks one of the great questions about our species: are we still evolving? There's no doubt that we're a product of millions of years of evolution. But thanks to modern technology and medicine, did we escape Darwin's law of the survival of the fittest? Alice follows a trail of clues from ancient human bones to studies of remarkable people living in the most inhospitable parts of the planet and the frontiers of genetic research, to discover if we are still evolving - and where we might be heading.