In the third part of his journey into the history of Christianity, Professor Diarmaid MacCulloch charts Orthodoxy's extraordinary fight for survival. After its glory days in the eastern Roman Empire, it stood right in the path of Muslim expansion, suffered betrayal by crusading Catholics, was seized by the Russian tsars and faced near-extinction under Soviet communism. MacCulloch visits the greatest collection of early icons in the Sinai desert, a surviving relic of the iconoclastic crisis in Istanbul and Ivan the Terrible's cathedral in Moscow to discover the secret of Orthodoxy's endurance.

In the fourth part of the series, Diarmaid MacCulloch makes sense of the Reformation, and of how a faith based on obedience and authority gave birth to one based on individual conscience. He shows how Martin Luther wrote hymns to teach people the message of the Bible, and how a tasty sausage became the rallying cry for Swiss Reformer Ulrich Zwingli to tear down statues of saints, allow married clergy and deny that communion bread and wine were the body and blood of Christ.

Professor Robert Bartlett explores the impact of the Normans on southern Europe and the Middle East. The Normans spread south in the 11th century, winning control of southern Italy and the island of Sicily. There they created their most prosperous kingdom, where Christianity and Islam co-existed in relative harmony and mutual tolerance. It became a great centre of medieval culture and learning. But events in the Middle East provoked the more aggressive side of the Norman character. In 1095, the Normans enthusiastically answered the Pope's call for holy war against Islam and joined the first crusade. They lay siege to Jerusalem and eventually helped win back the holy city from the muslims. This bloody conquest left a deep rift between Christianity and Islam which is still being felt to this day.

It bursts from the Sun with the power of ten thousand nuclear weapons... and when it hits our planet, it could create the largest disaster in recorded history. A magnetic storm from the Sun could wipe out electrical power, television, radio, military communication, and nearly every piece of electronics in the Northern Hemisphere. It's a "Solar Katrina" -- a planet-wide "hurricane" of magnetic forces that scramble all 21st Century technology, possibly for good. What causes this magnetic superstorm? Why is magnetism so powerful -- and yet so poorly understood? And is there anything we can do to prevent the Magnetic Storm?

They've discovered water on other planets, and snatched the actual building blocks of life from a comet's tail. But can space probes find a new Earth...and even make contact with alien life? In the 21st century, space probes are photographing, drilling and even sniffing new worlds in the quest for life, and scanning thousands of distant suns trying to detect Earth-like planets. It's only a matter of time before space probes unlock the secrets to extra-terrestrial life and the universe itself.

Our planet has amazing power, and yet that's rarely mentioned in our history books. This series tells the story of how the Earth has influenced human history, from the dawn of civilisation to the modern industrial age. It reveals how geology, geography and climate have been a far more powerful influence on the human story than has previously been acknowledged. A combination of epic story telling, visually stunning camerawork, extraordinary locations and passionate presenting combine to form a highly original version of human history" In the first episode professor Iain Stewart explores the relationship between the deep Earth and the development of human civilisation. He visits an extraordinary crystal cave in Mexico, drops down a hole in the Iranian desert and crawls through seven-thousand-year-old tunnels in Israel. His exploration reveals that throughout history, our ancestors were strangely drawn to fault lines, areas which connect the surface with the deep interior of the planet. These fault lines gave access to important resources, but also brought with them great danger.