The end of Main Street in San Luis, Ariz., is a border crossing station that connects the city to San Luis Rio Colorado in Mexico.

Our second story in the series airs today on NPR’s Weekend Edition Saturday. It is about Main Street in San Luis, Arizona, which runs straight into the border with Mexico. Listen to it on NPR’s website.

The first story of the series – “In Chattanooga, Main St. Is A Prostitution Strip” – aired today on NPR’s Weekend Edition Saturday.

On the surface, Main Street in Chattanooga, Tenn., looks nice. There’s a newly developed arts district with galleries, upscale restaurants, a packed breakfast joint called the Bluegrass Grill, even houses that have been certified as environmentally friendly. But if you stray from these newly renovated blocks, there’s a different side to Chattanooga’s Main Street.

“In Chattanooga, we have this underbelly,” Brother Ron Fender says. “You can walk down Main Street, and you don’t know that just over there, there’s prostitutes — or just over there is a camp where people sleep in the woods at night.”

Listen on NPR’s site, watch the video above or click on the Chattnooga feature in the gallery to see it within the Tennessee route.