Spanish Colonial Fortifications were military structures built by the Spanish Empire to protect their territories in the Americas and the Caribbean. These fortifications, such as castles and walls, were designed to defend against attacks from rival nations and pirates. They often featured thick stone walls, watchtowers, and strategic locations near coastlines or rivers. Many of these fortifications, like Castillo San Felipe del Morro in San Juan, Puerto Rico, showcase a blend of military architecture and local materials. They played a crucial role in the Spanish colonial strategy, helping to secure trade routes and maintain control over vast territories during the 16th to 18th centuries.