East Bay Walls

East Bay Walls (also called Berkeley Mystery Walls) are crude stone walls found throughout the hills surrounding the San Francisco Bay Area, extending as far as Chico, Red Bluff and Montague, California.[1] Built without mortar, they reach up to one meter in height and width, and extend from a few meters to over half a mile in length.[1] Materials range from basketball-sized rocks to sandstone boulders weighing a ton.[1] The exact age of the walls is unknown; some appear as mere rock piles while others show careful construction.[1] Many sections have sunk into the earth and become completely overgrown.[1]