This state park stands on the grounds of California's largest "hydraulic" mine, which started operation in 1855 and stopped a century later under protest of downstream farmers. Visitors can see huge cliffs carved by mighty streams of water, results of the gold mining technique of washing away entire mountains to find the precious metal-the eroded walls of the vast Malakoff Pit remain bare of vegetation, forming a raw badland amid lush mountain forests. The park also contains a 7,847 foot bedrock tunnel that served as a drain. The visitor center has exhibits on life in the old mining town of North Bloomfield. A few Gold Rush-era buildings survive, grouped in a pleasant tree-shaded setting at the site of historic North Bloomfield; the village reached a population high of 800 in the early 1880s.