TED
Since its founding in 1984, the TED nonprofit organization has hosted thousands of short speeches around the world on technology, entertainment, and design.
It began posting video of the presentations online in 2006, and there are now more than 2,100 TED Talks that have been viewed well over a billion times.
We've collected the 20 most popular presentations on TED's website, ranging from explorations of how to reimagine stress in your life to appreciating the power of introverts.