Today, technologies like Google, Siri, and Wolfram Alpha can answer virtually any question in milliseconds. So it’s refreshing to come across a mystery that takes a little longer to unravel.
I recently found the solution to a minor historical puzzle that’s been gnawing at me for almost two years, ever since I moved to the Dogpatch neighborhood of San Francisco to set up Xconomy’s Bay Area bureau. To find the answer I had to tie together clues from several different sources, including Google Earth.
This amazing piece of free software has been around since 2005 (I’ve written about it here and here), and it’s used by millions of people around the world to explore detailed images of the earth’s surface, the ocean floor, and even the Moon and Mars. But my little discovery reminded me that Google has made many unheralded improvements to the program over the years, including the addition, in early 2009, of historical imagery.
Using a simple slider, a Google Earth user can turn the clock backward and forward for certain locations, revealing pictures of vanished landscapes that are nearly as old as aerial photography itself. It’s a remarkable tool, and by telling my story perhaps I’ll inspire a few readers to experiment with it.
The Dogpatch is an industrial neighborhood bordering San Francisco’s southeastern shore. In the nineteenth century it was home to the city’s shipbuilding trade and associated industries, including steelmaking and gunpowder manufacturing. It reached a peak of prosperity sometime around World War I, spent the next 70 years slumping into decay, and has recently begun to come alive again as a center for tech startups, light manufacturing, hip restaurants, and live/work lofts like the one I rent.
The main drag through the Dogpatch is Third Street. Before the tidal flats in Mission Bay were filled in to create the land that’s now home to UCSF, a huge wooden structure called the Long Bridge linked the Dogpatch to central San Francisco. Third Street now follows the bridge’s path.
The mystery was this. One day in mid-2010, I was out walking my dog on Third Street between 22nd Street and 23rd Street, about three blocks east of my apartment, when I noticed that there’s a row of five buildings set at a 40-degree angle to the curb. All the other buildings on that block of Third Street are perpendicular to the street. But these five buildings cut through the block like a slash mark—see the snapshot at left from Google Earth.
One of these buildings is famous, at least to locals: it’s the Frisco Clubhouse of the Hells Angels Motorcycle Club. As it turns out, people in this neighborhood are rather fond of the Hells Angels. Their faux-threatening demeanor helps to keep the peace, which more than makes up for the noise from their choppers.
Once I’d spied the tilted clubhouse, of course, I wanted to know the story behind these odd buildings. On the surface, the idea that builders would place four sets of structures at a 40-degree angle to everything around them seemed like folly or insanity. But I’ve spent enough time staring at maps to know that such anomalies are usually just the remnants of older patterns in the urban landscape, laid out by earlier inhabitants for specific, if long-lost, reasons.
A brief digression shows that these reasons can usually be dug up. Potrero Hill lies just to the west of my loft building. If you walk around the neighborhood much—particularly the area around De Haro Street, between 15th and 18th Streets (where Zynga used to be headquartered, until its recent move to SoMa)—you’ll notice that there’s a diagonal slice through several blocks, running from northwest to southeast. The slice is even clearer in aerial images on Google Maps or Google Earth. And when you look at those images, the really interesting thing is that the slice disappears at 18th Street, then reappears at 22nd Street—just 100 yards from my west-facing window, in fact.
The obvious inference is that there used to be a railroad line cutting across and underneath Potrero Hill. And a little bit of research on Google reveals that this was, in fact, the case. The Ocean Shore Railroad laid the line and dug the tunnel around 1905. It turned out to be bad timing, as the 1906 earthquake did so much damage to other parts of the Ocean Shore’s trackage that the railroad eventually went bankrupt and sold the Potrero sections to the Western Pacific.
Bad luck struck again in 1960, when a fire inside the tunnel led to its collapse, causing sinkholes in the streets above. After the fire, the tunnel was supposedly filled with cement, and
