A Spanish fort is a military structure built by the Spanish during the colonial period to protect their territories from invasions and attacks. These forts were often constructed in strategic locations, such as coastal areas or near important trade routes, to defend against pirates and rival nations. They typically featured thick stone walls, bastions, and cannons. Many Spanish forts, like Castillo de San Marcos in St. Augustine, Florida, showcase unique architectural styles influenced by Renaissance and Moorish designs. Today, these historic sites serve as popular tourist attractions, offering insights into the military history and colonial life of the time.