I often go for hikes in the Marin Headlands just across the Bay from San Francisco. It's an easy destination on weekends when there is even a Muni bus that goes all the way to Rodeo Beach.

Several years ago on one of these hikes I was surprise by very dense fog that enveloped the hills all around me in a thick, puffy cloud. All outside sounds seemed to cease and I found myself all alone on Hill 88, which was a radar defense post back in the 1950s.

The base has been abandoned for many decades and in the dense fog the ruins looked much taller, darker and more doomed as I had ever seen them.