Fort Guijarros
...that the ten cannons of Fort Guijarros, built in 1797 as the first defensive fortifications for San Diego Bay, California, have been fired in action only twice since?
...that the ten <a href="./Cannon" id="mwEdw" rel="mw:WikiLink" title="Cannon">cannons</a> of <b id="mwEd0"><a href="./Fort_Guijarros" id="mwEd4" rel="mw:WikiLink" title="Fort Guijarros">Fort Guijarros</a></b>, built in 1797 as the first defensive <a class="mw-redirect" href="./Fort" id="mwEd8" rel="mw:WikiLink" title="Fort">fortifications</a> for <a href="./San_Diego_Bay" id="mwEeA" rel="mw:WikiLink" title="San Diego Bay">San Diego Bay</a>, <a href="./California" id="mwEeE" rel="mw:WikiLink" title="California">California</a>, have been fired in action only twice since?