9 mind-expanding podcasts to listen to if you only have 30 minutes

The average morning commute in the US is just shy of 30 minutes.

That's no fun if you spend it in rush-hour traffic, but it's a good time to try out a new podcast, especially one that upends the way you see and think about the world.

From business to history to psychology, here are some of the most mind-expanding podcasts that you can gobble up in a half-hour or less.