United States of America
The Old Plank Road is a plank road in Imperial County, California, that was built in 1915 as an east–west route over the Algodones Dunes. It effectively connected the extreme lower section of Southern California to Arizona and provided the last link in a commercial route between San Diego and Yuma.
Listen to the audio guide for Old Plank Road Free on WIP — starts by itself when you arrive, even with the screen off