Diarmaid MacCulloch traces the growth of an exuberant expression of faith that has spread across the globe - Evangelical Protestantism. Today, it is associated with conservative politics, but the whole story is distinctly more unexpected. It is easily forgotten that the evangelical explosion has been driven by a concern for social justice and the claim that one could stand in a direct emotional relationship with God. It allowed the Protestant faith to burst its boundaries from its homeland in Europe. In America, its preachers marketed Christianity with all the flair and swashbuckling enterprise of American commerce. In Africa, it converted much of the continent by adapting to local traditions, and now it is expanding into Asia. But is Korean Pentecostalism and its message of prosperity in the here and now an adaptation too far?

Diarmaid MacCulloch's own life story makes him a symbol of a distinctive feature about Western Christianity - scepticism, a tendency to doubt which has transformed both Western culture and Christianity. In the final programme in the series, he asks where that change came from. He challenges the simplistic notion that faith in Christianity has steadily ebbed away before the relentless advance of science, reason and progress, and shows instead how the tide of faith perversely flows back in. Despite the attacks of Newton, Voltaire, the French Revolutionaries and Darwin, Christianity has shown a remarkable resilience. The greatest damage to Christianity was actually inflicted to its moral credibility by the two great wars of the 20th century and by its entanglement with Fascism and Nazism. And yet it is during crisis that the Church has rediscovered deep and enduring truths about itself, which may even be a clue to its future.

Dr Thomas Dixon delves into the BBC's archive to explore the troubled relationship between religion and science. From the creationists of America to the physicists of the Large Hadron Collider, he traces the expansion of scientific knowledge and asks whether there is still room for God in the modern world. He looks at what happens when new scientific discoveries start to explain events that were once seen as the workings of God, and explains how some of our most famous scientists have seen God in the grandest laws of the universe. Finally, he finds intriguing evidence from brain science which hints that belief in God is here to stay.

Chaos theory has a bad name, conjuring up images of unpredictable weather, economic crashes and science gone wrong. But there is a fascinating and hidden side to Chaos, one that scientists are only now beginning to understand. It turns out that chaos theory answers a question that mankind has asked for millennia - how did we get here? In this documentary, Professor Jim Al-Khalili sets out to uncover one of the great mysteries of science - how does a universe that starts off as dust end up with intelligent life? How does order emerge from disorder? It's a mindbending, counterintuitive and for many people a deeply troubling idea. But Professor Al-Khalili reveals the science behind much of beauty and structure in the natural world and discovers that far from it being magic or an act of God, it is in fact an intrinsic part of the laws of physics. Amazingly, it turns out that the mathematics of chaos can explain how and why the universe creates exquisite order and pattern. And the best thing is that one doesn't need to be a scientist to understand it. The natural world is full of awe-inspiring examples of the way nature transforms simplicity into complexity. From trees to clouds to humans - after watching this film you'll never be able to look at the world in the same way again.

After 400 BC, a new philosophy was born in South east Asia, generated from the ideas of Buddha, a mysterious Prince from India who gained enlightenment while he sat under a large, shapely fig tree. He remains one of the most legendary and influential of all religious progenitors, but what of his actual life? In this biographical documentary, director David Grubin tells the historical tale of Gautama Buddha (563-483 BC), from his initial enlightenment through his death around the age of 80. In the process, Grubin makes an unusual point: that Gautama never once claimed to be God or God's emissary, but instead sought to find a way to bring peace and alleviation from suffering to others in a cruel and often insane world. In telling this story, Grubin combines a number of elements including original animations, testimony by contemporary Buddhists such as the 14th Dalai Lama Tenzin Gyatso, glimpses of sculptures and paintings that help tell Gautama's story, and much more. Narrated by Richard Gere

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.