Some photos of the Marin Headlands. This area has many historical fortifications
and bunkers dating from before the civil war up to the cold war.
This fort was started just before WWII and intended to be armed with
16" naval cannons. The site consists of an extensive tunnel system, rangefinding
station, a separate command station, a sub-level escape tunnel, and a separate
access tunnel through the hill behind it. The actual battery tunnels are
well sealed, but the access tunnels and gun turrets are open.