The digital era gives rise to unprecedented opportunity to exploit, and be exploited. Troves of child pornography are available at the click of a mouse. Who are these children - and who profits from their abuse? While facilitating the darker side of our impulses, technology is also being touted as a cure to rehabilitate predators. In this episode meet the children who are forced to perform sex acts on camera; people who use the same technology to protect kids and nab the perpetrators; plus, a pedophile who reveals the roots of his addiction.

As man moves to colonize the cosmos, the realities of sexual relationships and reproduction need to be addressed. Probe the physiological, psychological and cultural challenges of sex in space.

In this programme, Mary descends into the city streets to discover the dirt, crime, sex and slum conditions in the world's first high-rise city. This Rome is not the marble Rome we know, but a vast, messy metropolis with little urban planning, where most Romans lived in high-rise apartment blocks with little space, light, or even sanitation. Forced outdoors into the city streets, she reveals where they went to hang out, get drunk, have sex and get clean. She looks at the Forum as a place of gamblers, dentists and thieves, and she explores the lustiness of Roman bar life and jokes. Finally, exploring law and order from the bottom up, Mary examines how this city really worked. She meets Ancarenus Nothus, an apartment dweller who lived in fear of the rent collector; Notorious Primus, who wrote about his three great pleasures in life - baths, wine and sex; and Unlucky Doris, a seven-year-old girl killed in one of Rome's many fires.

Richard Dawkins deals with some of the philosophical and social ramifications of the theory of evolution. Dawkins starts out in Kenya, speaking with palaeontologist Richard Leakey. He then visits Christ is the Answer Ministries, Kenya's largest Pentecostal church, to interview Bishop Bonifes Adoyo. Adoyo has led the movement to press Kenya's national museum to sideline its collection of hominid bones pointing to man's evolution from ape to human.[5] The collection includes the Turkana Boy discovered by Kamoya Kimeu, a member of a team led by Richard Leakey in 1984. Dawkins discusses social darwinism and eugenics, explaining how these are not versions of natural selection, and that 'Darwin has been wrongly tainted'. He then meets with evolutionary psychologist Steven Pinker to discuss how morals can be compatible with natural selection. He goes on to explaining sexual selection, with peafowls as an example. To find out whether sexual selection plays a role for altruism and kindness among humans, he visits women who are looking for sperm donors, as well as a sperm bank manager. Dawkins also explains kin selection and selfish genes.

Presenter Michael Wood seeks out the achievements of the country’s golden age, discovering how India discovered zero, calculated the circumference of the Earth and wrote the world’s first sex guide, the Kama Sutra. In the south, he visits the giant temple of Tanjore and sees traditional bronze casters, working as their ancestors did 1,000 years ago.

Dr Michael Mosley traces the sinister ways the experimental psychology has used to try to control our minds. He finds that the pursuit of mind control has led to some truly horrific experiments and left many casualties in its wake. Extraordinary archive captures what happened - scientists systematically change the behaviour of children; law abiding citizens give fatal electric shocks; a gay man has electrodes implanted in his head in an attempt to turn his sexuality. Michael takes a hallucinogenic drug as part of a controlled experiment to try to understand how its mind-bending properties can change the brain. This is a scientific journey goes to the very heart of what we hold most dear - our free will, and our ability to control our own destiny.