“Why Not Die Trying?” — Devil’s Slide Base Station

Perched on the eroding seaside bluffs near Devil’s Slide, these hardened pill-boxes were a 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.