Examines the impact of racism in the 20th century. By 1900 European colonial expansion had reached deep into the heart of Africa. Under the rule of King Leopold II, the Belgian Congo was turned into a vast rubber plantation. Men, women and children who failed to gather their latex quotas would have their limbs dismembered. The country became the scene of one of the century's greatest racial genocides, as an estimated 10 million Africans perished under colonial rule.

The band heads to Nashville, Tenn. Dave sits down with Dolly Parton, Tony Joe White, Steve Earle, Willie Nelson, Emmylou Harris and producer Tony Brown to discuss Nashville's musical influences and the Nashville sound. Foo Fighters prepare to record at Southern Ground studio, owned by country musician Zac Brown, who also guests on the song 'Congregation'.

'Mormon Lost Boys' Young men have been thrown out of their homes because of an edict allowing polygamist church elders to monopolize young girls. 'The Fat Farms of Mauritania' In the West African country of Mauritania, parents send their daughters to rural fattening camps. 'Mumbai Slumscraper' A visit to Mumbai, where slums sit below billion-dollar, single-family skyscrapers.

'Deliver Us from Drought' - Over the past years, Texas has experienced the worst drought in its recorded history. 97% of the scientific community agrees that human activity has contributed to extreme weather patterns around the world. But many Texans--legislators, community leaders and citizens--don't attribute their drought to humans, and have taken few if any initiatives to limit the state's CO2 emissions, currently the highest in the country. "The Resource Curse" - As humanity's appetite for energy grows exponentially, the extraction industry scrambles to the most remote regions on Earth. In the undeveloped Melanesian country of Papua New Guinea, America's Exxon Mobil has staked its claim to a $19 billion liquid natural-gas project. While some see Exxon's mammoth presence as the catalyst that will usher the underdeveloped country into the 21st Century, others predict the initiative could plunge its people into civil war.

'The Coldest War': With the polar ice caps shrinking due to global warming, new trade routes are being exposed, along with billions of dollars' worth of natural-resource reserves. The five nations bordering the Arctic are readying themselves to fight for it. The problem is that there's one non-NATO country that already considers itself rightful owner of the region: Russia. With Vladimir Putin's recent military annexation of Crimea, there's a definite possibility its aggressions will boil over, returning the international community to precarious Cold War footing. We will head north to witness NATO forces participating in the largest polar military exercise in history. 'Heroin Warfare': Since the U.S. occupation of Afghanistan, heroin production in the region has skyrocketed, making the country the number-one producer by a large margin. Though Iran, Afghanistan's neighbor, is an ultraconservative country, Afghan heroin flowing across the border has actually caused Iran to have the worst heroin use problem in the world. Suroosh Alvi gets a rare look inside Iran to meet the suffering heroin addicts, and see how the country is coping with the illegal drug trade.

China's last empire, the Qing, lasted from 1644 to 1912. It began in violence and war as the Manchus swept down from the north, but invaders became emperors, with three generations of one family ruling the country. Among them, Michael Wood argues, was China's greatest emperor - Kangxi. Under the Qing, China doubled in size to include Xinjiang in the far west, as well as Mongolia and Tibet, creating the essential shape of China today. The new dynasty tolerated a diversity of cultures and religions, including Islam. In Kaifeng, Michael visits a women's mosque with a female imam, a delightful scene that ends with laughter and selfies! The Qing also undertook huge cultural enterprises. At a traditional printing house where the wood blocks are hand-carved, we see how the Complete Tang Poems were reproduced - all 48,000 of them. We travel through the wintry countryside to a remote village where a hardy audience watch open-air opera in the snow and visit a painter's studio, and 'storytelling' houses in Yangzhou. In the 18th century, China was arguably the greatest economy in the world, and we get a fabulous sense of the rich culture that came with prosperity. But then came the clash with the British, in the first Opium War, when a British expedition destroyed the Qing navy and extracted territory and trading rights. We leave with a glimpse of the future. 'Every dynasty has risen and declined,' says Michael, 'and has needed new life to regenerate, and this time the catalyst was the British.' Among the ports China ceded was an almost uninhabited island, Hong Kong, one of today's greatest financial centres, and Shanghai, a small town then but now one of the greatest cities in world.