Exploring the biggest questions of our time with the help of the world's greatest thinkers. Host Manoush Zomorodi inspires us to learn more about the world, our communities, and most importantly, ...

Salt and pepper, silver, pewter, charcoal. Whatever you call it, we all get gray hair at some point. But why do some people go gray in their 20s while others don’t see the first sign of silver until ...