Societies where people trust one another are healthier and wealthier. In the U.S. (and the U.K. and elsewhere), social trust has been falling for decades — in part because our populations are more diverse. What can we do to fix it?

The International Monetary Fund has long been the "lender of last resort" for economies in crisis. Christine Lagarde, who runs the institution, would like to prevent those crises from ever happening. She tells us her plans.