Graham-Dixon journeys to the country’s scorched centre to explore Spanish art of the 16th and 17th centuries. From the mystical world of El Greco to the tender genius of Velazquez, this was a moment so extraordinary it became known as the Golden Age. But beneath the glittering surface was a dark and savage heart. Travelling from the architectural jewel of Toledo to majestic Madrid, Andrew Graham-Dixon traces the rise and fall of the Spanish Empire, the brutal conquest of the New World, and the religious madness of the Inquisition, to discover how a history so violent could produce some of the most beautiful art ever seen.

Idolized in ancient Norse mythology as the protector god, Thor battles evil ogres and a giant serpent bent on destroying mankind. It's the quintessential fight for survival that culminates in a final showdown between good and evil. But was the rise and fall of the hero Thor ancient code for something greater? Today, new discoveries unlock the hidden truth behind the Norse god of Thunder. Able to wield thunder from his hammer, Thor was the most revered of the Norse gods, from fending humanity from the giants that brought calamity, to his pursuit of the Midgard Serpent. Though, his fate is told to sealed during Ragnarok, it is actually the invasion of Christianity that proves far more damning to this mighty god.

Mathematician Dr Hannah Fry explores the mystery of maths. It underpins so much of our modern world that it's hard to imagine life without its technological advances, but where exactly does maths come from? Is it invented like a language or is it something discovered and part of the fabric of the universe? It's a question that some of the most eminent mathematical minds have been wrestling with. To investigate this question, Hannah goes head first down the fastest zip wire in the world to learn more about Newton's law of gravity, she paraglides to understand where the theory of maths and its practice application collide, and she travels to infinity and beyond to discover that some infinities are bigger than others.
In this episode, Hannah goes back to the time of the ancient Greeks to find out why they were so fascinated by the connection between beautiful music and maths. The patterns our ancestors found in music are all around us, from the way a sunflower stores its seeds to the number of petals in a flower. Even the shapes of some of the smallest structures in nature, such as viruses, seem to follow the rules of maths. All strong evidence for maths being discovered. But there are those who claim maths is all in our heads and something we invented. To find out if this is true, Hannah has her brain scanned. It turns out there is a place in all our brains where we do maths, but that doesn't prove its invented.
Experiments with infants, who have never had a maths lesson in their lives, suggests we all come hardwired to do maths. Far from being a creation of the human mind, this is evidence for maths being something we discover. Then along comes the invention of zero to help make counting more convenient and the creation of imaginary numbers, and the balance is tilted in the direction of maths being something we invented. The question of whether maths is invented or discovered just got a whole lot more difficult to answer

Japan's role in World War II gets a whole new perspective in this consisting entirely of full colour footage, including colour films from Japan that were recently discovered. As the visuals of the world war take on a new vivid immediateness, the story of the rise of the militarists in Japan is told through the personal writings of the Japanese themselves. From the first overconfident tastes of victory, to the devastating losses that led to an unthinkable defeat amidst the ruins, the Pacific Theater of World War II is told through the Japanese's eyes.

Soldiers and officers continually came into conflict with their consciences. How much freedom did individuals have? Were they executing Hitler's criminal plans, or was it the Wehrmacht's war? There were crimes against humanity, against civilians, prisoners of war, and there was the Holocaust itself. The Trent Park records discovered and analysed by historian Sönke Neitzel, author of Tapping Hitler's Generals, show that the 84 German generals who were interned at Trent Park were aware of the severity of the war crimes they had been involved in and that some discussed them almost compulsively. They included the Commissar Order, to kill any Soviet commissar, and Rathenau's order to kill the Jews, including children.

From unexplained flashes in the night sky to flying saucers, this episode delves into the mysterious world of UFOs. How our drive to explain these bizarre phenomena, and desire to discover little green men, has in fact transformed our understanding of the universe