In this episode he traces India in the days of the Roman Empire. In Kerala the spice trade opened India to the world, whilst gold and silk bazaars in the ancient city of Madurai were a delight for visiting Greek traders. From the deserts of Turkmenistan Michael travels down the Khyber Pass to Pakistan to discover a forgotten Indian Empire that opened up the Silk Route and at Peshawar built a lost Wonder of the World.

Dr Michael Mosley seeks to establish the truth about meat. Every year, humans raise and eat 65 billion animals - nine animals for every person on the globe. In this eye-opening documentary, Michael examines the impact that this is having on the planet and finds out what meat eco-friendly carnivores should be buying. Is it better to buy free-range organic or factory-farmed meat? The answers are far from obvious.

One man's journey to discover the bitter truth about sugar. Damon Gameau embarks on a unique experiment to document the effects of a high sugar diet on a healthy body, consuming only foods that are commonly perceived as 'healthy'. Through this entertaining and informative journey, Damon highlights some of the issues that plague the sugar industry, and where sugar lurks on supermarket shelves. This will change the way you think about healthy food.

Investigative journalist Jeremy Scahill travels to Afghanistan, Yemen, Somalia, and other countries where the United States has taken military action in the War on Terror. In Afghanistan, he investigates the United States military and government cover-up of the deaths of five civilians, including two pregnant women killed by US soldiers from the Joint Special Operations Command. After investigating the attack, Scahill travels to other sites of JSOC intervention, interviewing both proponents and opponents, and the survivors, of such raids,including U.S. Senator Ron Wyden. Scahill also investigates the assassinations of American citizens Anwar al-Awlaki and his son Abdulrahman al-Awlaki, meeting with their family at their home in Yemen. Scahill suggests that the War on Terror is in fact a "self-fulfilling prophecy" and causes the radicalization of Muslims. He also discusses the case of Yemeni investigative journalist Abdulelah Haider Shaye who was detained, tried and sentenced on terrorism-related charges after reporting on American drone strikes.

Montezuma Dan Snow journeys to the ancient heart of Mexico in search of the lost civilisation of the Aztecs and their last and greatest ruler, Montezuma II (1502-1520). Montezuma inherited an empire of five million people, stretching from present-day Mexico to Nicaragua, from his uncle. His rule was marked by incessant warfare. Enemy states were growing more powerful and conquered tribes were becoming more rebellious. Within months of taking the throne in 1502, he went changed a man of good reason into a pitiless autocrat who declared himself a god, believing that fear and ruthlessness were the only ways to stop the empire falling apart. Yet it was at the hands of Cortes and the Spanish conquistadors that Montezuma met his downfall. But what was his relationship with Cortes, and why did such a ruthless leader submit to his captors with such relative ease? As Dan Snow visits the ruins and picks through current excavations, he pieces together the evidence of a gripping story: a divine tragedy of errors, the clash of civilisations, the end of a world - and a very human God.

It is a nightmare that has stalked us for centuries: hordes of human beings transformed into mindless, cannibalistic monsters. Could this civilization-ending nightmare become reality? Scientists have discovered pathogens that turn insects into the walking dead. New strains of viruses are attacking humans every day. Mathematicians have calculated the likelihood of surviving a zombie virus outbreak: they’re not hopeful. Now neuroscientists are discovering how easy it is for us to lose conscious control of our bodies. Are we at risk of becoming puppets? If we were in the middle of a zombie apocalypse, would we even know it?