Andrew Marr talks to Richard Sennett about increasing urbanisation. With half the world's population living in major cities, Sennett asks why the art of designing cities has declined so drastically in the last century. Iain Sinclair turns a critical eye on the grand plans for London's 2012 Olympics, and asks what will happen when the last race is run. Kate O'Regan was appointed as a judge in the Constitutional Court in South Africa by Nelson Mandela when he became President in 1994. She reflects on the role of the judiciary in building a modern democracy. And the advertising guru, John Hegarty reveals how you sell someone something they didn't even know they wanted. Over the last four decades he has transformed brands, famously linking Vorsprung durch Technik to Audi, and in a stroke, changing the perception of a staid car.