A public enquiry into a proposed 1000-cow mega-dairy in Powys begins.
1/3 Erica discovers that bees' sense of smell can be used to detect explosives and disease.
1/6 Michael Blastland explores the way human beings think, behave and make decisions.
Solar lamps are lighting parts of Africa the grid cannot reach. Tom Heap investigates.
Wednesday 6 March 2013