Castillo de San Marcos National Monument

St. Augustine’s Castillo de San Marcos National Monument, the oldest masonry fort in the United States, stands as a testament to 17th-century Spanish engineering. Built in 1672 to safeguard Spanish territories in the New World, the fort’s robust coquina walls have withstood the test of time, making it the only intact 17th-century fort in the country. Over the centuries, it changed hands from the Spanish to the British and then to the Americans, playing significant roles in both the Civil War and the Spanish–American War. Today, visitors can explore the fort’s historic ramparts, learn about its military past, and take in the panoramic views of St. Augustine.