If you’ve been to San Francisco, you’ve probably noticed those weird brick circles that are sometimes on the street. What are they? Decoration? Proof of alien life? Cat traps? As it turns out, it’s none of these! (Well, okay, maybe they can do double-duty as cat traps.) As it turns out, it’s history and infrastructure all rolled into one!
San Francisco is somewhat earthquake prone as we all know, and in 1906, a big one hit. How big? If it weren’t for the Galveston, TX Hurricane in 1900, it’d be the biggest natural disaster in American history. And it wasn’t just the earthquake itself, it caused a whole mess of fires. To keep such horrible fires from happening again, in 1909, the city began construction on the Auxillary Water Supply System, a system of reservoirs, pump stations, fireboats and cisterns.
And it’s that last one, cisterns, that are what these things are! They’re big, empty underground tanks that can be filled with water in the event of a conflagration too big for standard firefighting methods. And, well, we know what they look like on top, but this is what they look like inside.
Cool, huh? If you want more info, here’s a video explanation from the SF Exploratorium:
UpOut.Com has more photos, but here are some of our favorites: