Off-Ramp ® is a lively weekly look at Southern California through the eyes and ears of radio veteran John Rabe. News, arts, home, life... covering everything that makes life here exciting, enjoyable, and interesting.

Most of the bridges that cross the LA River are your standard single-deck bridge. They might be pretty to look at, but one of the bridges has a secret world beneath it, and there's a plan, at least, to open it up to the public.

Before 1927, crossing the 7th street Bridge was a traffic nightmare. Train tracks blocked traffic on both sides and city planners knew they had to build over them. But instead of tearing down the old bridge, they built a new span on top of the old one, and the space beneath has been sitting idle for 80 years. Arthur Golding, an architect who’s always had a passion for bridges, recently began a project to convert the unused space below the 7th Street Bridge into an open-air marketplace.

“It can be a kind of Mercado – I call it the Mercado del Rio – where there are shops, restaurants, and craft and art venues.”

Golding has put together a lengthy proposal full of drawings and measured floor plans - but he’s never actually been inside the space. He’s only looked at archived material from the L.A. City Bureau of Engineers, and some photos taken by a blogger named Joe Linton, one of the few people to have gone inside the bridge.

“We came out here one afternoon," Linton says. "And by hook or by crook, kind of a figured out a way in. From the outside it looks like this tiny space, but once you get in you realize it’s not small. And the views are incredible.”

Golding’s plan still has many obstacles before it breaks ground, including building at least one entry that doesn’t require risky climbing. But city officials think it’s an inspired idea, and have added it to a growing list of projects for the L.A. River.

More from Blogdowntown: River Revitalization Corp Sees a Retail Future for the Historic 7th Street Viaduct.