Three-part video series presented by the physician Professor Robert Winston explores the nature of our believes, the understanding of God in different times and different cultures, what it means to be a human.

He begins his search in the depths of the caverns in south-west France. The mysterious hand prints on the cave walls establish a connection between the supernatural powers inside the rocks.

Then he visits Teotihuacan, one of the largest ancient cities in the world. In the great temple human sacrifice practiced by the Aztec priests once upon a time.

He meets a Buddhist priest to understand Buddhism its teachings are similar atheism.

The last stop in this episode is Iran, the birth place of Zoroastrianism that is possibly the source of monotheistic religions.

[Credit: Atheist Movies]