Helen Zille has had a long career as a journalist, anti-apartheid campaigner and politician. She is a grandmother living in Cape Town, the city she ran as mayor from 2006 to 2009. But instead of enjoying her retirement in the Cape, as many inland South Africans like to do, the 74-year-old wants to move the other way. She plans to run for mayor of Johannesburg, the country’s commercial capital, next year.