The centerpiece of many a St. Augustine tour, the Castillo de San Marcos is most famous for its long history. Construction began on the fort in 1672, and it was completed in 1695, making it the oldest masonry fortification in the United States. Today, the Castillo de San Marcos is open to the public, offering tours and exhibits so tourists can learn more about Spanish Florida.

The Spanish founded St. Augustine in 1565, and it quickly became the most important city in the southeastern section of the New World, acting as a trading center for Florida and the Caribbean. However, the wealth passing through the city made it a prime target for pirates like Sir Francis Drake, who pillaged St. Augustine in 1586 on behalf of the British crown. St. Augustine was also targeted by local tribes, who performed successful raids throughout the 17th century. 

Finally, after English privateer Robert Searle sacked St. Augustine in 1668, the Spanish crown was convinced to build stronger fortifications protecting the city. The result was Castillo de San Marcos, a masonry bastion fort built out of a material called coquina – a type of sedimentary stone made of ancient shells. The fort was built mostly by native laborers from the nearby missions, although some skilled workers were brought over from Cuba to assist with construction.

After the Castillo de San Marcos was completed in 1695, St. Augustine would never again be successfully raided. The British would besiege the fortress in 1702 and again in 1740, but both attacks failed to break through. After the Spanish ceded Florida to the United States in 1821, the fort was used to house prisoners of war, including Seminole chief Osceola and several of his followers. Although Osceola was executed, several other Seminole prisoners led a daring escape in 1837 and continued their fight against the US troops.

To make the most of your next trip to Florida, check out our St. Augustine Self-Guided Walking Tour, or you can sign up for Action+ and gain access to over 100 tours for a single yearly price.