The Pythagorian philosopher Plato hinted enigmatically that there was a golden key that unified all of the mysteries of the universe. It is this golden key that we will return to time and again throughout our exploration. The golden key is the intelligence of the logos, the source of the primordial om. One could say that it is the mind of God. With our limited senses we are observing only the outer manifestation of the hidden mechanics of self similarity. The source of this divine symmetry is the greatest mystery of our existence.

In ancient Greece the Asclepian healing temples recognized the power of the primordial spiral which is symbolized by the rod of Asclepius. To this day, this symbol of our evolutionary energy remains as the logo of the American Medical Association and other medical organizations worldwide. The snake, the downward direction, is the manifested spiral, the evolutionary energy of the world.

We move around in space, but we are stuck in a prison of time moving ever forwards. Einstein said, 'The distinction between past, present and future is only a stubbornly persistent illusion.' Is our experience of the ticking clock merely a trick of the mind? Could science ever make the clock move backwards? Experiments in quantum physics are showing that the future influences the present: what happens later limits the choices we think we have now. The laws of physics say visiting or talking to ourselves in the past is possible – but changing history once we get there is not.

If you had less than one second to make a life-or-death decision to shoot a man who might be armed with a lethal weapon, what would you do? Would the ethnicity of the man affect your decision? Are you sure? The outcome – whatever your race – will surprise you. Brain imaging studies are showing that negative cultural stereotypes hijack everyone’s subconscious decision-making. But some science says we can overcome bigotry through exposure, self-awareness and flexible social networks… and, most controversially of all, ultra-violent video games!

As Michelle's loved ones cope with her sudden death, her work to unmask the Golden State Killer lives on. After inheriting Michelle's 37 boxes of case files, Paul Haynes and Billy Jensen work alongside Patton Oswalt, to finish her book.

There is a tendency to deny German culture the equal reverence of Italy or Spain, and this enlightening new series provides a wonderful opportunity to explore a great, yet often neglected, artistic tradition whose influence has been just as profound. Andrew Graham-Dixon concludes his exploration of German art by investigating the dark and difficult times of the 20th century. Dominating the landscape is the figure of Adolf Hitler, failed artist, would-be architect and obsessed with the aesthetics of his 1,000-year Reich". In a series of extraordinary building projects and exhibitions, Hitler waged a propaganda war against every form of modern art as a prelude to unleashing total war on the whole of Europe. After the war the shadow of the Third Reich persisted, Germany remained divided and traumatised. How would artists deal with a past that everybody wanted to forget? Journeying through the work of Otto Dix and George Grosz and the age of the Bauhaus to the post-war painters Georg Baselitz, Hilla Becher and the conceptual artist Joseph Beuys is a long and strange journey, but the signs that art has a place at the heart of the new reunited Germany are clearly visible.