Here you see the ruins of a base-end “fire station” that was created shortly after the attack on Pearl Harbor when the U.S. entered the Second World War. Scouting stations like this one, which is on the Muir Woods lookout point (see second picture) were built along the northern California coastline to watch out for enemy ships.
As you can see from the drawing on the third photo, these “gopher holes,” as the men stationed here called them, were equipped with a telescope to watch for potential enemy attacks and a minimum of living quarter space.