Today nine nations collectively control more than 15,000 nuclear weapons, each hundreds of times more powerful than those dropped on Hiroshima and Nagasaki. In a talk at TEDWomen 2016, Erika Gregory, managing director of the MacArthur-supported N Square Collaborative, argues that the next generation must address the unfinished challenge of disarmament started decades ago. She calls on today’s rising leaders to pursue an ambitious goal of ridding the world of nuclear weapons by 2045.