Raising the gun

SAN FRANCISCO--The days when our greatest fears were that the Japanese or some other then-enemy might invade our coasts or attack from the oceans are long gone, and so it's easy to forget that much of the first half of the 20th century was spent preparing for just such an occurrence. In fact, worries that we had to protect the coasts from attack lasted well into the Cold War.

Yet while many people never knew about that history, or had long forgotten it, the relics of a century of coastal fortifications are still very much in evidence in and around San Francisco.

Today, San Francisco is thought of mainly as a picturesque tourist destination. But for decades, it was considered America's most valuable Pacific port and was home to a wide variety of military installations. As a result, military planners put a huge amount of energy, starting in the Civil War era, into protecting the Pacific coast from invasion or attack.

And that's why there is a treasure trove of old batteries and other remnants of original fortifications up and down the coast in and around the city.

This is a 6-inch disappearing gun that is mounted at Battery Chamberlin, in the shadow of the Golden Gate Bridge, in San Francisco. This battery was meant to protect some of the city's most exposed beaches from direct attack from the open Pacific Ocean. The gun, while an original, was placed at Battery Chamberlin in the 1970s, when the site was opened to the public as a museum.

It was called a disappearing gun because it was meant to be housed low to the ground and invisible to the sea, and was raised up only when firing. When it would discharge its six-inch shell, it would recoil back down low to the ground. The idea was to protect the gun itself from attack, and to keep the lowest possible profile.