Ideas about the soul and the afterlife, sin and God's purpose have shaped human thinking for thousands of years. Religious rituals remain embedded in the major events of our lives.
Can science provide answers to the big questions we used to entrust to religion?
Evolutionary biologist Richard Dawkins considers whether science will replace religion as a source of inspiration and guidance in our lives. Can science bring understanding in the face of death, help us tell right from wrong, or reveal the meaning of life?
Episode 1: Life After Death
Richard Dawkins explores what science can tell us about death. It's a journey that takes him from Hindu funeral pyres in India to genetics labs in New York.
Dawkins brings together the latest neuroscience, evolutionary and genetic theory to examine why we crave life after death, why we evolved to age and how the human genome is something like real immortality - traits inherited from our distant ancestors that we pass on to future generations.
He meets a Christian dying of motor neurone disease, reminisces about the Wall Street Crash with a 105-year-old stockbroker, and interviews James Watson, the geneticist who co-discovered the structure of DNA.
Episode 2: Sin
If there is no God watching us, why be good? Richard Dawkins examines sin. He asks whether the old religious rules about what is right and wrong are helpful and explores what science can tell us about how to be good.
Dawkins journeys from riot-torn inner city London to America's Bible Belt, building a powerful argument that religion's absolutist moral codes fuel lies and guilt.He finds the most extreme example in a Paris plastic surgery clinic that specialises in making Muslim brides appear to be virgins once again.
But what can science and reason tell us about morality? Through encounters with lemurs, tango dancers, the gay rights campaigner Matthew Parris and the scientist Steven Pinker, Dawkins investigates the deeper roots of moral behaviour in our evolutionary past.
Episode 3: The Meaning of Life
Why does an atheist bother to get up in the morning? That's the question Richard Dawkins seeks to answer as he continues his exploration of the big questions of life in a world shaking off religious faith.
In a journey that takes him from the casinos of Las Vegas to Buddhist monasteries in the foothills of the Himalayas, Richard Dawkins examines how both religious and non-religious people struggle to find meaning in their lives.
He looks at how our existence is ruled by chance, meeting people whose fate was to be born into extreme poverty in India's slums and the survivors of a natural disaster in Joplin, Missouri, a city ripped apart in 2011 by a tornado on a random course.