TED is a non-profit organization devoted to Ideas Worth Spreading. Started as a four-day conference in California 30 years ago, TED has grown to support its mission with multiple initiatives. The two annual TED Conferences invite the world’s leading thinkers and doers to speak for 18 minutes or less. Many of these talks are then made available, free, at TED.com. TED speakers have included Bill Gates, Jane Goodall, Elizabeth Gilbert, Sir Richard Branson, Nandan Nilekani, Philippe Starck, Ngozi Okonjo-Iweala, Sal Khan and Daniel Kahneman.