These are photos from the Presidio area of San Francisco (around the southern end of the Golden Gate Bridge). I have a bunch more photos from this area that I haven't posted online yet. Hopefully I will get to them soon.
The Presidio until recently was a military base, though its last period of large scale use was during WW2 when it was fortified against Japanese invasion with large coastal defense gun batteries. But even before then, the region was heavily fortified with coast defense guns starting during the Civil War. This is the only west coast area to receive full US Civil War era coastal defenses. But the military history of the Presidio is even older than that. Before California became a part of the United States, the Presidio was the site of a Spanish military garrison.
Anyway, on to the photos...
One of the old Gun Battery foundations.
WW2 era Bunker
A hallway in a Civil War era fort beneath the Golden Gate Bridge.
Sutro Bath Ruins at night.
Each of the images is a link to a larger size copy of the image that will open in a new window.