Andrew Marr with the physicists Brian Greene and Brian Cox explores the universe in all its wonder. And he attempts to understand our relation to parallel universes, which can be separated from us by enormous stretches of time and space, or hover just millimetres away. The science writer, Angela Saini, looks at why India is so successful in producing the next generation of doctors and scientists, in her book, Geek Nation.

Producer: Katy Hickman.