In this episode Brian Cox visits South East Asia's 'Ring of Fire'. In the world's most volcanic region he explores the thin line that separates the living from the dead and poses that most enduring of questions: what is life? The traditional answer is one that invokes the supernatural, as seen at the annual Day of the Dead celebrations in the Philippine highlands. Brian sets out to offer an alternative answer: one bound up in the flow of energy through the universe. On the edge of Taal Volcano lake, Brian demonstrates how the first spark of life may have arisen. Here, heat energy from the inner Earth forces its way to the surface and changes its chemistry, just as it did in our planet's infancy. It is now believed that these chemical changes set up a source of energy from which life first emerged. Today, virtually all derives its energy from the Sun. But there's a paradox to this as according to the laws of physics energy can neither be created nor destroyed. So life doesn't 'use' ...