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.

Źródło: World Heritage Convention
http://whc.unesco.org/en/list/841