Mariana dives into the world of international scamming to understand how it all works.

Mariana investigates fentanyl, a contributor to the deadliest drug crisis in U.S. history.

Mariana meets the craftsmen who make and sell the world's finest counterfeit U.S. dollars.

Mariana attempts to understand the vanity, insecurity and greed that drives steroid use.

Mariana sets out to understand the ugly business of illicit sex in America.

Mariana retraces one of the world's most intractable smuggling routes, following cocaine's path arou...

Mariana van Zeller tackles the black market for tigers and tiger parts, so secretive and dangerous t...

Mariana uncovers a supply chain of firearms being smuggled into the hands of drug cartels.

Mariana van Zeller investigates underground plastic surgery, from motel-room operations to a deadly...

Mariana meets the villains behind an exploding online romance scam.

Mariana sets off on a wild journey through California’s black market for weed, which has mushroomed...

Mariana van Zeller investigates outlaw motorcycle gangs known as 1% clubs, learning about the bonds...

Mariana van Zeller follows a meth superhighway from a cartel-run lab in Sinaloa across the border an...

Mariana exposes a racist underground movement hellbent on a violent future.

Mariana tracks a smuggling route of stolen cars from the U.S. to West Africa.

Mariana investigates a new breed of cocaine trafficker: lady bosses.

Mariana investigates the criminals destroying the Amazon rainforest.

Mariana explores the billion-dollar underworld of illegal fishing.

A look at the complex inner-workings of the global underworld, black and informal markets.

Mariana goes in search of the elusive chemists who make the world's LSD.

Mariana exposes the dangers of the growing and deadly ghost guns industry.

Mariana investigates how illicit oil is fueling terrorist groups worldwide.

An alarming message from her son's middle school about MDMA sparks van Zeller into high gear. She tr...

Mariana explores surrogacy's dark side; a babies-for-cash black market.

Mariana investigates the lucrative black market for private data.

Mariana journeys into gangland to understand the violence plaguing LA.

Mariana embeds with crypto scammers who show her how they make millions.

Mariana investigates the growing popularity of bare-knuckle fighting.

Mariana explores the growing influence of Mexican cartels in the U.S.

Mariana travels to Southeast Asia's epicenter of romance and investment scams, known as "pig butcher...