St. Augustine, Florida, is home to the historic Spanish fort, Castillo de San Marcos, which is one of the oldest masonry forts in the United States.

To safeguard their interests in the area, the Spanish built Castillo de San Marcos at St. Augustine, Florida, between 1672 and 1695. Now a component of the Castillo de San Marcos National Monument, the fort is a significant historical site that symbolizes the impact of Spanish colonization in the Americas. A significant historical site, St. Augustine is the oldest continuously inhabited European-established settlement in the continental United States. Although Florida is home to important towns like Miami, Jacksonville, and Fort Lauderdale, the Castillo of San Marcos is situated in St. Augustine.