2021 Castillo de San Marcos $7.95 Priority Mail Stamps Self-Adhesive Sheet

The stamp art features a digital illustration of the Castillo based on a contemporary photograph. With a view toward the northeast corner of the fortress, the artwork captures it in the golden glow of sunrise over Matanzas Bay. 

The Castillo was constructed between 1672 and 1695, while Spain controlled “La Florida,” the east coast of today’s Florida. The Castillo’s building material helped ensure its effectiveness. Coquina, a soft and porous limestone conglomerate of small seashells, proved ideal for a fort because cannon balls did not shatter it but rather burrowed in and stuck there.