Situated atop a California coastal promontory known colorfully as Devil’s Slide are the crumbling remains of a squat cement building that looks as though it is about to tip over and slide into the sea.
Devil’s Slide was the location of a military triangulation station and observation site used during World War II as part of the harbor defense of San Francisco. Prior to the advent of radar, military personnel would use binoculars and compasses to search for ships at sea and relay their coordinates to a central post. By combining information from multiple observation posts, a ship’s precise location could be determined by triangulation.
