Castillo de San Marcos has been under attack since construction began in 1672. Enemy gunfire struck these walls with little damage, but time and weather have taken a visible toll. Preservation crews constantly inspect the fort and carry out work to stabilize it, including removing water from the moat to help support the foundation. Bright coquina marks recently completed projects and will fade over time as it blends with the surrounding stonework. As the historic white plaster weathers away, the coquina stone is exposed, and preservation efforts have stabilized a coquina chimney even though its outer plaster layer has not been replaced.