Visited this site in May 2018.

Castillo de San Pedro de la Roca del Morro is located about 10 km to the south from Santiago de Cuba on a strategic rock controlling harbor entrance. After over 150 years of painful planning, designing and construction, many times interrupted by the military attacks from competing colonial powers and pirates and earthquakes, it was more or less completed only in 1700s. The fortress served as prison once pirate threat declined in 18th century (you could visit some tiny prison cells). Castillo is considered the best-preserved Spanish colonial military fortress. It is quite compact site with stunning views over the sea, deep mounds, sharp edges and everything you expect from a military fortress. For a European eye is does not look something special but taking into consideration all the circumstances Castillo found its deserved place in the WHS list. Inside there are some rooms dedicated to the Caribbean piracy.

All in all, good site and pleasant excursion from Santiago de Cuba.