The disappearance and fate of the tomb of Alexander the Great in Alexandria is among the most momentous and tantalising of all the mysteries we have inherited from the ancient world. Generations of scholars and historians have succumbed to the allure of the quest.
Now archaeologist Pepi Papakosta is on a mission to find Alexander the Great's lost tomb. Excavating in a public garden in the center of Alexandria, Egypt, the city he founded 2,300 years ago, she has discovered a rare marble statue of Alexander, Greek treasures and secret tunnels. But Pepi's biggest find is an extraordinary discovery even she was not expecting.

Rivers provide the essentials of life: fresh food and water. They often provide natural highways and enable us to live in just about every environment on Earth. But rivers can also flood, freeze or disappear altogether!Cities - Surviving the Urban Jungle Human Planet joins Sam Niang, a Laotian fisherman, as he walks a high wire strung above the raging Mekong River rapids on an extraordinary commute to work. There's also a look at the remarkable partnership between Samburu tribesmen and wild elephants in their search for water in the dried-out river beds of Northern Kenya. Plus, a father who must take his two children on a six-day trek down a frozen river - the most dangerous school run on Earth, and the ice dam busters of Ottowa with their dynamite solution to a city centre hold-up.

This scientific detective tale tells the story of a remarkable group of pioneers who wanted to reach the ultimate extreme: absolute zero, a place so cold that the physical world as we know it doesn't exist, electricity flows without resistance, fluids defy gravity and the speed of light can be reduced to 38 miles per hour. Absolute zero became the Holy Grail of temperature physicists and is considered the gateway to many new technologies, such as nano-construction, neurological networks and quantum computing. The possibilities, it seems, are limitless. The first episode Chronicles the major discoveries leading towards the mastery of cold, beginning with King James I's court magician, Cornelius Drebbel, who managed to air condition the largest interior space in the British Isles in 1620. Other stories will include the first "natural philosopher," Robert Boyle, a founder of the Royal Society in Great Britain; the Grand Duke Ferdinand II de Medici's involvement in the creation of the first thermometer; the establishment of the laws of thermodynamics by three young scientists, Sadi Carnot, James Joule and William Thomson; and Michael Faraday's critical achievement in liquefying several other gases which set the stage for the commercial application of cold to refrigeration and air conditioning.

The final episode explores dinosaurs' extraordinary ability to survive. Featured dinosaurs include the bizarre magyarosaurus, which lived in the shadow of the biggest flying animal - hatzegopteryx - and showed an amazing adaptation to island life; and the weird nothronychus, a carnivore that gave up meat eating. This astonishing capacity to evolve into ever more diverse and bizarre forms meant that dinosaurs not only spread throughout the world, but also dominated life upon it for more than 160 million years. It was only an unprecedented extraterrestrial event that finally saw the end of planet dinosaur.

In this documentary we will be transported into the world of ants. What animal has achieved immortality? What animal is the most warlike? What animal has the greatest supercity on the planet? Not man but ants. They are the real success story. It is only their tiny size and our vanity that allows us to hold onto the myth of our supremacy. Ants rule the planet. They are found in more habitats from far northern Finland to the sweltering tropics. The largest colony known of these insects is in Japan, where 306 million ants, with 1 million queens, in 45,000 colonies spread over 270 hectares. The fiercest warriors on earth are the slave maker ants. Other ants have barracks and sentry posts to protect themselves against surprise attack.

This is the ultimate hidden kingdom - the urban jungle. In the colourful and chaotic streets of Rio, a young marmoset is separated from his street gang and forced to confront of the dangers of the city alone. In the futuristic metropolis of Tokyo, a rhinoceros beetle escapes his captors and begins an extraordinary journey through this alien world to find sanctuary.