Mines and Submarine Defenses
If the big guns failed to stop an enemy vessel far offshore, the next line of defense was three minefields containing over 600 underwater mines outside the Golden Gate. An antisubmarine net located inside the Gate would prevent any submarine that penetrated the minefield from entering the bay.
Did You Know?
Muir Woods National Monument was the first National Monument created from a private land donation and the first created in an urban area.