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.

Iain sets sail on one of the fastest racing boats ever built to explore the story of our turbulent relationship with the wind. Travelling to iconic locations including the Sahara desert, the coast of West Africa and the South Pacific, Iain discovers how people have exploited the power of the wind for thousands of years. The wind is a force which at first sight appears chaotic. But the patterns that lie within the atmosphere have shaped the destiny of continents, and lie at the heart of some of the greatest turning points in human history.

Sir Attenborough's journey begins in a forest near his childhood home in Leicester, where a fossil discovery transformed our understanding of the evolution of complex life. Travelling to the fog bound coastline of Newfoundland and the Australian outback, Sir Attenborough unearths the earliest forms of animal life to exist on Earth. These bizarre and wonderful creatures are brought to life with the help of cutting edge scientific technology and photorealistic visual effects. From the first animal forms that moved to the first mouths that ate, these were creatures that evolved the traits and tools that allow all animals, including ourselves, to survive to this day.

In the third programme of the series, Aleks gives the lowdown on how, for better and for worse, commerce has colonized the web - and reveals how web users are paying for what appear to be 'free' sites and services in hidden ways. Joined by some of the most influential business leaders of today's web, including Eric Schmidt (CEO of Google), Chad Hurley (CEO of YouTube), Bill Gates, Martha Lane Fox and Reed Hastings (CEO of Netflix), Aleks traces how business, with varying degrees of success, has attempted to make money on the web. She tells the inside story of the gold rush years of the dotcom bubble and reveals how retailers such as Amazon learned the lessons. She also charts how, out of the ashes, Google forged the business model that has come to dominate today's web, offering a plethora of highly attractive, overtly free web services, including search, maps and video, that are in fact funded through a sophisticated and highly lucrative advertising system which trades on what we users look for. Aleks explores how web advertising is evolving further to become more targeted and relevant to individual consumers. Recommendation engines, pioneered by retailers such as Amazon, are also breaking down the barriers between commerce and consumer by marketing future purchases to us based on our previous choices. On the surface, the web appears to have brought about a revolution in convenience. But, as companies start to build up databases on our online habits and preferences, Aleks questions what this may mean for our notions of privacy and personal space in the 21st century

Dr Aleks Krotoski concludes her investigation of how the World Wide Web is transforming almost every aspect of our lives. Joined by Facebook founder Mark Zuckerberg, Bill Gates, Al Gore and the neuroscientist Susan Greenfield, Aleks examines the popularity of social networks such as Facebook and asks how they are changing our relationships. And, in a ground-breaking test at University College London, Aleks investigates how the Web may be distracting and overloading our brains.

Is mankind alone, or are there aliens out there, either waiting to be discovered, or on their way to find Earth? Professor Brian Cox spends this episode asking such questions, and what he discovers may raise a few eyebrows. He begins by exploring the human race's efforts to find neighbours in outer space, including the launch of two golden discs containing a greeting from Earth in the 1970s; they are still travelling and are now the most distant man-made objects from the planet. Brian also meets members of the Search for Extra-Terrestrial Intelligence, who have been monitoring radio signals for 50 years without success, before discussing the ingredients needed to make an intelligent civilisation with astrophysicist Dr Frank Drake.