When we look up into the sky it appears we live in a universe that is filled with light. But scientists are now certain there is far more matter in the dark portions of our universe that we can’t see or touch. There’s something hiding in the shadows. Cosmologists agree that 'dark matter' has helped shape our Universe, but now they need to figure out what dark matter is. What’s going on in this hidden world? Could it have formed its own dark stars, planets, and even life forms? Could this Shadow Universe threaten our world of light?

Long ago, two species of human beings coexisted on Earth until competition drove one of them to extinction. This program, set in the southwest of France 35,000 years ago, reconstructs the life in the Neanderthal world at the time Cro-Magnons first entered the scene. All aspects of Neanderthal clan life are examined, including tool- and weapon-making, hunting and gathering, health and healing, childbirth, rituals, and making fire. Footage of skeletal remains and the scholarly research of eminent paleontologist Chris Stringer and Oxford University's Paul Pettitt support the documentary.

Beginning with the separation of the fuzzy thinking and pious fraud of astrology from the careful observations of astronomy, Sagan follows the development of astronomical observation. Beginning with constellations and ceremonial calendars (such as those of the Anasazi), the story moves to the debate between Earth and Sun-centered models: Ptolemy and the geocentric worldview, Copernicus' theory, the data-gathering of Tycho Brahe, and the achievements of Johannes Kepler (Kepler's laws of planetary motion and the first science-fiction novel).

Brian asks how, from a lifeless cosmos, it is possible that a planet can produce the more than eight million species we know of.

What is the universe made of? If you answered stars, planets, gas and dust, you'd be dead wrong. Thirty years ago, scientists first realized that some unknown dark substance was affecting the way galaxies moved. Today, they think there must be five times our understanding of the universe and the nature of reality itself has drastically changed over the last 100 years - and it's on the verge of another seismic shift. In a 17-mile-long tunnel buried 570 feet beneath the Franco-Swiss border, the world's largest and most powerful atom smasher, the Large Hadron Collider, is powering up. Its goal is nothing less than recreating the first instants of creation, when the universe was unimaginably hot and long-extinct forms of matter sizzled and cooled into stars, planets, and ultimately, us. These incredibly small and exotic particles hold the keys to the greatest mysteries of the universe. What we find could validate our long-held theories about how the world works and what we are made of -- or, all of our notions about the essence of what is real will fall apart.

Dr Francesca Stavrakopoulou asks whether the ancient Israelites believed in one God as the Bible claims. She puts the Bible text under the microscope, examining what the original Hebrew said, and explores archaeological sites in Syria and the Sinai which are shedding new light on the beliefs of the people of the Bible. Was the God of Abraham unique? Were the ancient Israelites polytheists? And is it all possible that God had another half?