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?

The dome that crowns Florence's great cathedral of Santa Maria del Fiore, the Duomo, is a masterpiece of Renaissance ingenuity and an enduring source of mystery. Still the largest masonry dome on earth, it is taller than the Statue of Liberty and weighs as much as an average cruise ship. Historians and engineers have long debated how its architect, Filippo Brunelleschi, kept the dome perfectly aligned and symmetrical as the sides rose and converged toward the center." More than four million bricks could collapse at any moment -- and we still don't understand how Brunelleschi prevented it. To test the latest theories, a team of U.S. bricklayers will help build an experimental "mini-Duomo" using period tools and techniques.

Placebos come in all shapes and sizes, but they contain no active ingredient. They are the miracle pills that shouldn't really work at all. Now they are being shown to help treat pain, depression and even alleviate some of the symptoms of Parkinson's disease. It seems they're not acting alone. The placebo effect is intertwined with how is did the healthcare. Explores why they work, and how we could all benefit from the hidden power of the placebo.

Professor Richard Fortey delves into the fascinating and normally-hidden kingdom of fungi. From their spectacular birth, through their secretive underground life to their final explosive death, Richard reveals a remarkable world that few of us understand or even realise exists - yet all life on Earth depends on it. In a specially-built mushroom lab, with the help of mycologist Dr Patrick Hickey and some state-of-the-art technology, Richard brings to life the secret world of mushrooms as never seen before and reveals the spectacular abilities of fungi to break down waste and sustain new plant life, keeping our planet alive. Beyond the lab, Richard travels across Britain and beyond to show us the biggest, fastest and most deadly organisms on the planet - all of them fungi. He reveals their almost magical powers that have world-changing potential - opening up new frontiers in science, medicine and technology.

Let's go behind the scenes at NASA to discover how it is preparing for its most ambitious and daring mission: to land men - and possibly women - on the surface of Mars. It's over 40 years since Neil Armstrong made the first human footprint on the moon. But getting to the red planet would involve a journey of at least three years. Meet the scientists and engineers who are designing new rockets, new space suits and finding ways to help astronauts survive the perils of this long voyage. And it turns out that having the 'right stuff' for a mission to mars might not be quite what you expect.

An unconventional biography about an Indian Swami who brought yoga and meditation to the West in the 1920s. This feature documentary explores the life and teachings of Paramahansa Yogananda, who authored the spiritual classic Autobiography of a Yogi, which has sold millions of copies worldwide and is a go-to book for seekers, philosophers and yoga enthusiasts today. It was the only book that Steve Jobs had on his iPad, and he arranged to give away 800 copies of it to the dignitaries who attended his memorial service. It was also a point of entry into Eastern mysticism for George Harrison, Russell Simmons and countless yogis. By personalizing his own quest for enlightenment and sharing his struggles along the path, Yogananda made ancient teachings accessible to a modern audience, attracting many followers and ultimately helping millions of seekers today to turn their attention inwards, bucking the temptations of the material world in pursuit of self-realization.