gabby ferriera

David Middlecamp/San Luis Obispo Tribune

For more than a century, mecury mines were active across San Luis Obispo County. The roughly 150 mines not only drove the county's economy, they helped establish Cambria as a city in the 19th century. They also played a role in America’s history—from the California Gold Rush to World War II. All of the county's mines have long since shuttered, but are still hiding in plain sight.