Com­mer­cial and polit­i­cal rival­ries in the Caribbean region in the 17th cen­tu­ry result­ed in the con­struc­tion of this mas­sive series of for­ti­fi­ca­tions on a rocky promon­to­ry, built to pro­tect the impor­tant port of San­ti­a­go. This intri­cate com­plex of forts, mag­a­zines, bas­tions and bat­ter­ies is the most com­plete, best-pre­served exam­ple of Span­ish-Amer­i­­can mil­i­tary archi­tec­ture, based on Ital­ian and Renais­sance design prin­ci­ples.