We dig into the world of archaeology this week to uncover what DNA is revealing about how humans domesticated plants and livestock. We also delve into the story of stonehenge and hear how scientists are using new isotope techniques to find out how it was built and what when on there. We also trace the history of the civilisation that carved the Nazca lines in South America and then disappeared without trace, but why? Plus, we hear about a new way to combat allergies with a course of injections, how music could improve your health, and how fish elect their leaders. And in kitchen science we show you how to make you own desktop siege weapon!