Eunice Hunton Carter, a granddaughter of slaves, went on to become the lawyer who built the case against Charles “Lucky” Luciano, one the 20th century’s most powerful criminal kingpins. It was an assignment fraught with danger, but one Carter performed with tenacity, intelligence and a sense of mission, discovering the Achilles heel of a man who’d evaded prosecution for years.

Gabriella Gómez-Mont is neither an urban planner nor an engineer nor a politician. She’s an artist. But as creative director of Mexico City’s Laboratorio para la Ciudad (Laboratory for the City), she has tackled some of the thorniest problems confronting the modern metropolis—with astonishing success. She and her team launched one of the biggest open data projects ever seen, drawing numbers from institutions and individuals, building map upon map of their city, to better understand challenges as varied as traffic deaths and social isolation.

Today, cities as far flung as Seoul and Manila seek Gómez-Mont’s expertise. As host Sarmishta Subramanian puts it: “Her power of one is in a sense the power of millions—a faith in the talents and wisdom and energy of ordinary citizens, in ordinary neighbourhoods. A belief that change can be made thoughtfully, and for the better.”

One spring day, Bradley Birkenfeld boarded a flight out of Geneva, beginning a journey that would make him one of the greatest whistleblowers in financial history. The former banker with UBS provided information to U.S. authorities that would shatter Swiss banking secrecy and lead some 14,000 well-heeled Americans to fork over an astounding US$5 billion in unpaid taxes.