Fort Matanzas is an old fortification built in the early 1740s by the Spanish forces who tried to conquer Florida. It is situated in the southern mouth of the Matanzas River, in the Rattlesnake Island, as a protection to the Matanzas Inlet, which can be used as an entrance to St. Augustine, Florida. It used coquina to build the site.

Fort Matanzas only fired on an enemy on one occasion. That was in 1742, when British forces attacked the site with 12 ships. The Spanish lost total control of Florida in 1763 and regained power over it again twenty years later, but the fort wasn?t used much, really. Even the US didn?t find a use for this site, and it started to get ruined.

After getting restored in 1916, the site was made a National Monument in 1924.