Spanish forts were military structures built by the Spanish Empire to protect their territories and trade routes during the Age of Exploration. These forts were strategically located along coastlines and near important cities to defend against pirates and rival nations. They often featured thick stone walls, bastions, and moats to enhance their defensive capabilities. Many famous Spanish forts still exist today, showcasing unique architectural styles and historical significance. Notable examples include Castillo San Felipe del Morro in San Juan, Puerto Rico and Castillo de San Marcos in St. Augustine, Florida. These sites attract tourists and serve as reminders of the colonial era.