Historic site, northeastern Florida, U.S. Established in 1924, it is the 25-acre (10-hectare) site of the oldest masonry fort in the U.S., built by the Spanish (1672–95) to protect St. Augustine. The fort played an important role in the Spanish-English struggle for the Southeast (circa 1670–1763). In the 19th century it served as a U.S. military prison.
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