"I will take St. Augustine or leave my bones before its walls," claimed British General James Oglethorpe in 1740. He did neither. While he did raze part of the Florida city, he could not crack the Castillo de San Marcos and retreated from Spain's impenetrable fortress after a 38-day siege. The Castillo never fell to an enemy attack—only to international treaties.
Today the Spanish fort—a national monument supervised by the National Park Service—is a museum of American military history. Begun in 1672, the fort protected St. Augustine and controlled the shipping routes between the New World and Europe. Its walls were the heart of its defenses. Built of coquina (seashells crushed together over millions of years), they were impervious to cannon fire. Heavy balls either bounced off the walls or embedded themselves without cracking the defenses.
The Castillo survived at least 15 attacks, mostly from British pirates, and in 1702 and 1740 it withstood two serious sieges by the British Army. The first came by sea from Charles Town (present-day Charleston, South Carolina) during Queen Anne's War. St. Augustine's residents fled into the fort for the two-month siege until the Spanish fleet, sailing from Cuba, relieved the city. The British were forced to scuttle their fleet and walk home.
The second attack came during the War of Jenkins' Ear, when Oglethorpe set out from the newly established colony of Georgia and captured a number of Spanish forts before laying siege to the Castillo. Almost in response to Oglethorpe's claim of leaving his bones at the walls, Spanish governor Manuel de Montiano said, "I will defend St. Augustine with the last drop of my blood." He did not need to. Oglethorpe's naval blockade was porous, and a small Spanish ship made it out of the fort to sound an alert. Other ships were later able to resupply it. Oglethorpe's 27-day bombardment of the fort proved ineffective and he, too, was forced to retreat.
Over the intervening years the fort changed hands from the Spanish to the British and back to Spain after the Revolutionary War. It became an American possession when Florida was ceded to the United States in 1821. Early during the first year of the Civil War, a lone Union Soldier occupied the fort. He refused to surrender it without a receipt from the Confederacy, which he received. Union forces returned on 11 March 1862 when the USS Wabash sailed into Matanzas Bay to find the fort abandoned. Although it became a national monument in 1924, the Castillo was pressed into service during World War II as a radio station monitoring U-boat operations.
In addition to being the oldest masonry fort in North America, the Castillo de San Marcos is also the only surviving 17th-century fort on the continent. Its distinctive architecture features the bastion system of fortification; four prominent bastions project from each of the square fort's corners. The strongpoint appears much as it did at its final completion in 1756. Cannon are still placed along the walls, and the impressive view of Matanzas Bay and the Atlantic Ocean attests to the Castillo's strategic importance. The 20.5-acre monument site also features a walled section of the defense line that surrounded St. Augustine, including the original city gates.
Visitors can take a self-guided tour through the fort, where artifacts, dioramas, and models in the different rooms help tell the story of the Castillo's colorful past.
Volunteers dressed in period clothing frequently demonstrate musket and rifle fire, and park rangers are knowledgeable and eager to answer any questions. They also give talks on the fort's defenses and history.
The Castillo's fee is $6 for adults, which permits seven days' admission, and there is no charge for children 15 years and younger accompanied by an adult. The fort is open to the public from 0845 to 1715 every day of the year except 25 December. The park grounds are closed from midnight until 0530. Visit the museum's website here.