Castillo de San Marcos: A Historical Fortress Made of Seashells
Located on the western shore of Matanzas Bay in St. Augustine, Florida, the Castillo de San Marcos stands as a testament to centuries of American history. It holds the distinction of being the oldest masonry fort in the continental United States and is a unique architectural marvel, built from a material native to the area: coquina.
A Fortress Forged from Coquina The fort's most distinctive feature is its construction material. The walls were built from coquina, a type of sedimentary rock composed of ancient seashells and limestone. This unusual material was first used by the Spanish in 1672 to build a stronger defense for St. Augustine after earlier wooden forts had succumbed to both Native American attacks and hurricanes. The coquina's porous nature allowed it to absorb cannonball impacts rather than shatter, providing an incredibly effective defense against enemy fire.
A History of Transformations The Castillo de San Marcos has a rich and varied history. Built by the Spanish, it was later renamed Fort St. Mark during the British occupation and then Fort Marion under U.S. Army control. It served as an active military fort through the Spanish-American War, though it was fortunately spared from destruction. It was even a storage facility for military supplies and a focal point for British operations. Despite its strategic importance, the fort was a frequent target for attacks, including from plantation owners in northern Georgia.
The fort remained in use until 1933 when it was deactivated and converted into a National Monument. Today, it is maintained by the National Park Service, preserving its legacy for future generations.
Visiting the Fort The Castillo de San Marcos National Monument is open daily from nine to five and is a popular destination for tourists. Visitors can explore the historic buildings, walk along the fortress walls, and learn about its storied past. While the fort's main parking lot can be busy with tour buses, visitors can still find parking nearby. An "America the Beautiful" annual pass provides free admission for the pass holder and up to three guests. However, it's important to note that for the preservation and safety of the monument, pets are not allowed inside the fort.
