For the first time in human history more than half of us live in cities. Vibrant, complex, colossal - what drives their success? Johannesburg is a city that's had to grow up fast. Founded on gold and riven by apartheid, its many and diverse citizens are finding common ground. In one day in this complex city we meet the inspiring young chatshow host with a vision; cut diamonds worth thousands of dollars; and enter the building designed to transform Soweto's future. Show less