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

Corey Feldman (star of Friday the 13th: The Final Chapter) narrates Crystal Lake Memories, which features interviews with approximately 150 cast and crew members from all twelve Friday the 13th films and the syndicated television series, many of whom have never before appeared in on-camera interviews. Interview subjects include Kane Hodder, Robert Englund, Tom Savini, Danielle Panabaker, Sean S. Cunningham, Derek Mears, Betsy Palmer, Wes Craven, Robert Shaye, Alice Cooper and many more

Author Henry Hitchings explores the lives and works of Britain's radical and pioneering 18th-century novelists who, in just 80 years, established all the literary genres we recognise today. It was a golden age of creativity led by Daniel Defoe, Jonathan Swift, Henry Fielding, Laurence Sterne, Fanny Burney and William Godwin, amongst others. Robinson Crusoe, Gulliver's Travels, Tom Jones and Tristram Shandy are novels that still sparkle with audacity and innovation. On his journey through 18th-century fiction, Hitchings reveals how the novel was more than mere entertainment, it was also a subversive hand-grenade that would change British society for the better. He travels from the homes of Britain's great and good to its lowliest prisons, meeting contemporary writers like Martin Amis, Will Self, Tom McCarthy and Jenny Uglow on the way.

Loot found secreted in pagan graves in Norway provides some major clues that point to Viking perpetrators following the discovery of murder victims in Wales and a monastery razed to the ground in Scotland.

Even after thousands of years of ice crushing the northern hemisphere and temperatures of 20 degrees lower than those of today, many of the great giants of the ice age still walked the earth. It was only when the world had warmed up again that mammoths, woolly rhinos, sabre-toothed cats, giant ground sloths and glyptodonts finally became extinct. Professor Alice Roberts sets off on her last voyage back to the Ice Age to discover why.

Part 2 examines how the freewheeling modernism that had shocked audiences in the first two decades of the century came under state control. Initially, many practitioners thought the totalitarian regimes would be good for music and the arts. What followed in Germany was a ban on music written by Jews, African-Americans and communists, while in the Soviet Union there was a prohibition on music the workers were unable to hum. After the cataclysm of the 1940s, a new generation of composers - Boulez, Stockhausen, Xenakis, Nono, Ligeti - turned their back on what they saw as the discredited music of the past and tried to reinvent it from scratch. Or, at least, from serialism, which became as much of a straitjacket as totalitarianism's strictures had been. But from this period of avant-garde experimentation, which many listeners found baffling and terrifying, came some of the most influential and radical musical innovations of the century.