The Castillo de San Marcos site is the oldest masonry fort in the United States. It is located in the city of St. Augustine, Florida. Construction was begun in 1672 by the Spanish when Florida was a Spanish territory.

This is the closest thing to a medieval castle that I've seen in North America. Its a really beautiful building.

The American narrative centers around Boston with its religious pilgrims and revolutionaries, but there is certainly something alluring about the south of the 1600s, with its walled cities, forts, artillery, sailing ships, pirates, sand, sun, and palm trees.

Castillo de San Marcos - Wikipedia, the free encyclopedia