Kern River is near Bakerfield, and highly unknown by most Angelinos (L.A. residents). It has an loads of outdoor activities like mountain-biking, hiking, tubing, white water kayak and rafting, and rock-climbing.
Sutro Baths are a lesser known attraction in San Francisco. The three acres baths were opened in 1894 as the world's largest indoor swimming pool establishment. Now it lies in ruins along the Pacific Coastline.