Today nine nations collectively control more than 15,000 nuclear weapons, each hundreds of times more powerful than those dropped on Hiroshima and Nagasaki. We don't need more nuclear weapons; we need a new generation to face the unfinished challenge of nuclear disarmament started decades ago. Nuclear reformer Erika Gregory calls on today's rising leaders -- those born in a time without Cold War fears and duck and cover training -- to pursue an ambitious goal: ridding the world of nuclear weapons by 2045.