1950s San Francisco, as seen through a submarine periscope

In 1951, the U.S.S. Catfish, a WWII-era diesel submarine, cruised into San Francisco Bay. The crew snapped a handful of pictures through the periscope, showing what the city and Alcatraz looked like from the submariners' perspective.

It's a bit eerie to see the city through the periscope's reticles, almost as if it were a target. It offers a historical perspective a largely pre-skyscraper San Francisco, but also creates the sense that the city being spied on.

You can see more photos from the Catfish at SF Gate.

San Francisco in 1951 as seen from a U.S. Navy submarine [SF Gate via Laughing Squid]

1950s San Francisco, as seen through a submarine periscope

1950s San Francisco, as seen through a submarine periscope