This little fort was an interesting piece of history. You need to take a short ferry ride to access Fort Matanzas (no charge). It is a National Monument managed by the National Park Service.
Soldiers were rotated from St. Augustin for one-month tours at the fort with one officer, four infantrymen, and two gunners (that's it!) A maximum of 50 could be deployed to this remote outpost when international tensions increased.
The fort could cover the inlet with five guns and holes in the south wall of the tower allowed the infantry men to fire their muskets from inside the fort. After thwarting attempts to gain the inlet in 1742, the fort never again fired its guns in battle.
View from the top of the inlet.
This is one of the two remaining original cannons (and, of course, John).