Hardly anyone nowadays seems to carry much cash, never mind carrying around a bunch of $100 bills. So why does the amount of physical cash in circulation — especially big denominations like the $100 bill — keep increasing? There's a pretty obvious answer. All those dollars are being laundered and used by criminal enterprises. In this episode, we speak with journalist Oliver Bullough, author of Everybody Loves Our Dollars: How Money Laundering Won, about this cash paradox. We discuss how cartels balance their books by trading drugs for farm equipment, the gigantic parallel financial system that undergirds global money laundering networks, and why money laundering resembles Renaissance-era banking.