Australian JEREMY HEIMANS is a lifelong activist. He is the co-founder and CEO of Purpose, an organisation that builds and supports social movements around the world. In 2005, he co-founded the political organisation GetUp!, which now boasts more members than all of Australia's political parties combined. HENRY TIMMS is President and CEO of 92nd Street Y and co-founder of #GivingTuesday, an international day of philanthropy.