Rome was once a largely democratic society, with regular elections. This Republic lasted for 500 years, but then came Tiberius Gracchus. He believed in the ideals of the Republic - fairness, decency and justice for everyone -but was appalled by Rome's aristocrats' treatment of the poor. So he unleashed the power of the mob upon the streets of Rome, with devastating consequences.

Gravity is the most powerful and exacting force in the universe. It is pervasive and penetrating. Gravity binds us together, its reach hangs stars in the sky and its grip crushes light. Gravity holds planets together, and leashes them to their suns. Without gravity, stars, comets, moons, nebulae, and even the Earth itself would not exist. Explore how science and humanity discovered, overcame and utilized gravity. Learn what it takes to propel objects into the heavens, to ride a wave or to ski down a slope. Take a front row seat as an astronaut subjects himself to the weightless wonders of the specially modified aircraft used to train astronauts known as the "Vomit Comet."

A journey through the dramatic and destructive years of the French Revolution, telling its history in a way not seen before - through the extraordinary story of its art. Our guide through this turbulent decade is the constantly surprising Dr Richard Clay, an art historian who has spent his life decoding the symbols of power and authority.

Dr Adam Rutherford tells the extraordinary story of the scientific quest to discover the secrets of the cell and of life itself. Every living thing is made of cells, microscopic building blocks of almost unimaginable power and complexity. The first part explores how centuries of scientific and religious dogma were overturned by the earliest discoveries of the existence of cells, and how scientists came to realize that there was, literally, more to life than meets the eye.

Right now, you're hurtling around the Sun at 64,000 miles an hour. In the next year, you'll travel 584 million miles, to end up back where you started. In this spectacular series, presenters Kate Humble and Dr Helen Czerski follow the Earth's voyage around the Sun for one complete orbit, to witness the astonishing consequences this journey has for us all. From seasonal extremes to destructive weather, they travel the world to experience the great events that are shaped by our journey around the Sun." They venture back in time to show how the Earths orbit has changed, and the astounding effect this has had on the planet. For the first time ever, this astonishing series charts the progress of the Earth as it undertakes its incredible annual orbit around the Sun. From stunning space imagery to in-your-face storm chasing, this series showcases the incredible power of our planets epic journey around the Sun. In this first episode they travel from July to the December solstice, experiencing spectacular weather and the largest tides on Earth. To show how the Earth's orbit affects our lives, Helen jumps out of an aeroplane and Kate briefly becomes the fastest driver on Earth.

This programme focuses on the most famous Roman of all - Caesar. Charming, savage, power-crazed, opportunistic and brilliant, he overthrew a 500-year-old Republic and began the age of the emperors.