The Darien Gap is the world's most dangerous migrant route. CNN chronicled 5 days on the route

There's only one way to walk from South to Central America — a route so fraught with danger that no one with any other option would choose it. It's called the Darien Gap, 66 miles of treacherous mountains, mud and jungle. Yet last year a quarter of a million people attempted the crossing.

The U.S. government recently pledged that its intelligence forces will assist Colombia and Panama to dismantle the smuggling rings that operate the Gap. But for now, the numbers are growing.

CNN chief international correspondent Nick Paton Walsh recently made the trek, chronicling the journey in a mini-documentary called "The Trek: A Migrant Trail to America." He joins host Robin Young to talk about the trek, and the policies and corruption that fuel it.