The Key to the Cosmos

The second in Professor Jim Al-Khalili's three-part documentary about the basic building block of our universe, the atom. He shows how, in our quest to understand the tiny atom, we unravelled the mystery of how the universe was created. It's a story with dramatic twists and turns, taking in world-changing discoveries like radioactivity, the atom bomb and the big bang. All this forms part of an epic narrative in which the greatest brains of the 20th century competed to answer the biggest questions of all - why are we here and how were we made?