This episode of the documentary series focuses on the new giants, the heavyweights of the dinosaur world. It is only in recent years that experts have unearthed the biggest dinosaurs that ever lived. One monster eclipsed all others; more than seven times as heavy as diplodocus was the immense argentinosaurus - a single backbone was bigger than a human. For years, these giants were considered immune to attack from any predator - until the discovery of mapusaurus, a new giant killer whose fate appeared to be inextricably linked to argentinosaurus

Professor Jim Al-Khalili tells the electrifying story of our quest to master nature's most mysterious force - electricity. Until fairly recently, electricity was seen as a magical power, but it is now the lifeblood of the modern world and underpins every aspect of our technological advancements.Without electricity, we would be lost. This series tells of dazzling leaps of imagination and extraordinary experiments - a story of maverick geniuses who used electricity to light our cities, to communicate across the seas and through the air, to create modern industry and to give us the digital revolution. Episode one tells the story of the very first 'natural philosophers' who started to unlock the mysteries of electricity. They studied its curious link to life, built strange and powerful instruments to create it and even tamed lightning itself. It was these men who truly laid the foundations of the modern world. Electricity was without doubt a fantastical wonder. This is the story about what happened when the first real concerted effort was made to understand electricity; how we learned to create and store it, before finally creating something that enabled us to make it at will - the battery.

Professor Brian Cox examines how it was that in a universe made of stars, rocks and endless space, a conscious civilisation was born. His latest adventure takes him from a submerged space station in Star City on the outskirts of Moscow, to Ethiopia, high above in the Great Rift Valley, where he encounters the geladas, mankind's distant ancestors. Despite once being Africa's most successful primate, a species who at one time roamed across the entire continent, these days they are found in one just place in the remote Ethiopian Highlands. Cox investigates why these ancestors retreated, yet modern mankind has expanded across the planet.

Legendary oceanographer and TED prize winner Dr. Sylvia Earle is on a mission to save our oceans. Mission Blue is part action-adventure, part expose of an Eco-disaster. More than 100 scientists, philanthropists and activists gather in the Galapagos Islands to help fulfill Dr. Earle's lifelong wish: build a global network of marine protected areas, like underwater national parks, to protect the natural systems that keep humans alive.
As the expedition ends, the Deep water Horizon oil well explodes. With oil gushing into the Gulf of Mexico, Sylvia and an environmental dream team race around the world trying to defend her 'Hope Spots'.

Richard Rudgley goes in search of evidence of the barbarians of the dark ages, people whose names have for 1500 years been bywords for mindless brutality. The real truth about the barbarians who marched across Europe during the Dark Ages is more shocking than what you may know. Where did they come from? Who are their descendants? Are any of their techniques and inventions still used? Richard discovers the secrets of forgotten empires, and of mighty clashes throughout Europe. The art, society and cultural legacy of the barbarians are shown to have shaped and moulded the destiny of Europe even more than the Roman Empire.
In the first part of the journey through the Dark Ages we will be tracing the legacies of the Huns, Vandals and Goths, to ask whether the 'dark ages' represent a resurfacing of much older tribal lines. Sites in Austria show how sophisticated pre-Roman communities had become with evidence of stunning craftsmanship and sophisticated farming techniques which defy the image of a mindless rabble we have come to accept without challenge.

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.