This fort is a picture of Castillo de San Marcos, which is the oldest masonry fort in the United States. But of course the Lord has been our fortress longer than that. When we abide in His shelter, we are safe.
The LORD is my rock, and my fortress, and my deliverer; my God, my strength, in whom I will trust; my buckler, and the horn of my salvation, and my high tower. Psalm 18:2