Portobelo is a port city in Panama, established during the Spanish colonial period. Located on the northern part of the Isthmus of Panama, it has a deep natural harbor and was used as a center for silver exporting before the mid-eighteenth century. Today Portobelo is a sleepy city with a population of fewer than 3,000. In 1980 the ruins of the Spanish colonial fortifications, along with nearby Fort San Lorenzo, were designated as a UNESCO World Heritage Site.