Five miles south of San Francisco you will find a a coastal promontory that is called “Devil’s Slide” with a hanging bunker. It lies on the San Mateo County coast between Pacifica and Half Moon Bay. The bunker is divided in two parts that are built on a thick pillar of sandstone. They were actually used to observation during pre-radar days and was a part of the San Francisco Harbor Defense.
There were six military structures at the Devil’s Slide: three concrete and steel observation pill-boxes, two concrete and earth bunkers, and a reinforced steel observation tower. The pill-boxes were used as hardened observation posts, and one of the bunkers was used as a communications and command post. The site was sold to a private owner in 1983, but some of the structures remain. Today it looks all old and rusty. Speaking of bunkers, take a look at these Russian ones.