The old Spring Valley Aqueduct in the San Francisco Bay Area is a bemusing secret trail through nature for wayward travelers prefering the less beaten path.

In the East Bay parklands of the San Francisco Bay Area near Fremont, California, there is a curious little trail known as the Secret Sidewalk. Well, it’s not really a sidewalk but rather the top of a strcuture that originally functioned as an aqueduct built by the Spring Valley Water Company about 100 years ago.
The half-buried concrete tunnel runs all the way from Calaveras Reservoir in the East Bay to San Francisco, at one point passing through the enchanting Sunol Water Temple.

The intent behind building the aqueduct was to provide fresh water for the city. Irvington Pumping Station lifted the water to Crystal Springs Reservior via the Pulgas Water Temple, also on the peninsula.
However, the local water table dropped quickly, and the Spring Valley aqueduct ceased operation after only three years use.

Today, Spring Valley Aqueduct isn’t good for much except as an amazing trail to hike along, walking through the open spaces of parkland on a readymade sidewalk of sorts. The surrounding area, which is otherwise untouched by civilization, is owned by the local government and walled off behind “no trespassing” signs.
Today, the Secret Sidewalk is also a gathering place for graffiti artists and teenage parties, who sneak into the area to enjoy the pleasant seclusion of a secret place only they know about.







