Where did everything in our universe come from? How did it all begin? For nearly a hundred years, we thought we had the answer: a big bang some 14 billion years ago. But now some scientists believe that was not really the beginning; our universe may have had a life before this violent moment of creation. Take the ultimate trip into the unknown, to explore a dizzying world of cosmic bounces, rips and multiple universes, and finds out what happened before the big bang. Horizon takes the ultimate trip into the unknown, to explore a dizzying world of cosmic bounces, rips and multiple universes, and finds out what happened before the big bang.

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.

Follow three professional gamers from around the world as they compete for a million dollar prize in the first Dota 2 International Tournament. In recent years, E Sports has surged in popularity to become one of the most widely-practiced forms of competitive sport today. A million dollar tournament changed the landscape of the gaming world and for those elite players at the top of their craft, nothing would ever be the same again

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.

Ancient Aliens explores the controversial theory that extraterrestrials have visited Earth for millions of years. From the age of the dinosaurs to ancient Egypt, from early cave drawings to continued mass sightings. In this episode researchers discuss the possibility that the great technological developments made by inventor Nikola Tesla were inspired by extraterrestrials

Bitcoin is a peer-to-peer monetary system in which all transaction records are public. Participants can use its open-source software to transfer virtual currency to one another as easily as they might send an email. Bitcoin opens an uncharted world of new possibilities to explore. We'll follow the stories of entrepreneurs and startups that are helping shape the new financial frontier. We'll look at the competitive mining market and the various subcultures within the Bitcoin community." You'll encounter a variety of characters and opinions as we examine the social and political impact of an open-source digital currency. Will the rise of Bitcoin bring a monetary paradigm shift that will forever change the world? Supposedly invented by a mysterious Japanese man named Satoshi Nakamoto (whose current whereabouts are unknown). Because it is designed to have an absolute ceiling of 21 million Bitcoins in circulation (not anticipated until 2040), and the system has no central depository or administrative authority, it has great appeal to libertarians and others who seek alternatives to a perceived corrupt, manipulative banking infrastructure and excessive government regulations. Its low processing fees compared with those of mainstream credit-card companies also hold considerable allure for merchants.