The drug MDMA is disturbingly popular in the U.K., where dealers smuggle it into music festivals and raves for eager customers.

In the poorest areas of Rio de Janeiro, elite teams of police officers risk their lives fighting brutal drug gangs with nothing to lose.

Follow the flow of smuggled hash as criminals transport it from Morocco, across the Strait of Gibraltar, up the coast of Spain and into France.

Meth smugglers and law enforcement officials play a high-stakes game of cat and mouse around Phoenix and the U.S.-Mexico border.