Here's an episode from Slate Money: Money Talks. Host Felix Salmon is joined by journalist Mariana van Zeller, who has spent years reporting on black and gray markets around the world and has a new podcast, The Hidden Third, that delves into these powerful underground economies. They’ll get into what Mariana has seen embedded with criminal operators, from the surprisingly mundane to the darker side of working outside the system. Podcast production by Jessamine Molli and Cheyna Roth.