The Darin Gap is a lawless wilderness on the border of Colombia and Panama, teeming with everything from deadly snakes to antigovernment guerrillas. The region also sees a flow of migrants from Cuba, Africa, and Asia, whose desperation sends them on perilous journeys to the U.S. Jason Motlagh plunged in, risking robbery, kidnapping, and death to document one of the world's most harrowing treks. Read