The fortification of Fort Alcatraz began in 1853. It is all a matter of history, if anyone wanted to dig it up. Apparently, the radar detection of underground structures (not unusual for a coastal fort) occurred in 2019. Similar coastal forts can be found in
Washington state.
That fact there was a military installation on that island should not cause concern.
What should cause concern is that our government knew and never told us about it.
The fortification of Fort Alcatraz began in 1853. It is all a matter of history, if anyone wanted to dig it up. Apparently, the radar detection of underground structures (not unusual for a coastal fort) occurred in 2019. Similar coastal forts can be found in Washington state.