Scattered around San Francisco are a total of 177 large cisterns buried beneath the streets.
Their presence is visible at many intersections in the shape of large brick circles embedded in the pavement.
San Francisco is the only city in the world to have such a system.
A circle of bricks marking the position of a subterranean cistern.
Within three days of the earthquake, fires destroyed approximately 25,000 buildings on 490 city blocks.
San Francisco’s early settlers were no stranger to fires.
A few months later, a ship went up in flames as it was preparing to sail.
This was the first great fire which devastated San Francisco.
Fire in San Francisco Bay, 1856.
It was the most devastation fire to date.
Hardly six months passed when yet another fire started, completely gutting ten blocks and partially destroying another six.
San Francisco Mission District burning in the aftermath of the San Francisco Earthquake of 1906.
Then the ground shook on April 18, 1906, and the citys water pipes sprouted leaks everywhere.
Consequently, the fire department lost water pressure at the same time that busted gas lines sparked a conflagration.
Eventually, it was water from these cisterns that helped firefighters save many neighborhoods from complete destruction.
These cisterns are standalone reservoirs and are not connected to the systems water supply.
Since the 1906 earthquake more than a century ago, the cisterns have not been used.
But they are still down there and regularly maintained ready to save the city when the next calamity strikes.
Photo:Mark Hogan/Wikimedia Commons
Inside a cistern in the Mission District, San Francisco, California.
Photo:Robin Scheswohl/Wikimedia Commons
A manhole cover over a cistern in San Francisco.
