This group periodically meets and then drives out to various Cache Creek Watershed-area trailheads.
The organizer, Andrew, and several of the other hikers were quite knowledgable on the flora, fauna, geography, and history of the area.
This was the "Wide Awake Mine" hike, and indeed, forgotten back in the foothills of Lake County, California, are several old mine sites which were abandoned long decades ago.
Interestingly, near to many of the mines were hot springs, and pre-automobile, folks would horse-n-buggy into the countryside to sit in sulfur-reeking, mercury-heavy waters.
Here, Sulfur Creek is slowly eating the cast iron bathing tub. The water was about 80 degrees and quite smelly.