Get a behind-the-scenes peek at San Cristobal Fort, one of the UNESCO-designated fortresses that guard San Juan Bay. Puerto Rico’s capital is featured on many Holland America Line cruises to the Caribbean; spend your day touring the Bacardi rum distillery, viewing Taino petroglyphs at Cueva Ventana, or visiting the only tropical rainforest within the U.S. A late-evening departure allows time to kayak one of Puerto Rico’s bio-luminescent bays.