Slaves in Modern Britain
Three women are freed after being kept as slaves for 30 years in south London. How could they have remained undiscovered for so long?
Also on the programme: the new Chinese outlook on investing their wealth overseas - but what if they want to send in Chinese workers as well?
And how do you start a farming revolution in Africa without removing the farmers already on the best land; we have a special report from Tanzania.
We hear about the Canadian city which has decided to abolish doorknobs - yes, really.
We've got live guests in Delhi, and also Brisbane, where the national cricket teams for England and Australia are battling it out for The Ashes.
And our special guest Hilary Mason in New York tells out about the new science of data - and the way it's going to change the world.