05/28/2026
In 1672, with no walls around the town, the Spanish began carving a fortress out of seashells. Everyone thought it was madness โ soft stone, against cannon fire?
More history & lore in the link in bio โ
The stone was coquina: compressed seashells quarried from nearby Anastasia Island, soft enough to cut with a saw. Then November 1702 came. The British sailed in, burned the town to the ground, and turned their guns on the fort. Fifteen hundred people had fallen back inside its walls.
The cannons fired for fifty days. And the shell stone held โ the porous coquina absorbed the cannonballs instead of shattering, swallowing the shot. Some are still lodged in the walls today.
The fort was besieged twice and never taken. Five flags flew over it, four different names, three centuries โ and it changed hands five times without once being captured in battle. The town burned and rebuilt around it. The fort never moved.
It still stands on the bay at St. Augustine โ the Castillo de San Marcos, the oldest masonry fortress in America, never taken by force in 330 years. A fort built out of seashells, that never fell.