Explore the bastions, dungeons and secret tunnels of Castillo San Felipe del Morro (El Morro) and Castillo San Cristóbal . Both are part of San Juan National Historic Site , which preserves the largest Spanish fortification in the New World.
Make a pilgrimage to the statue of La Rogativa , a tribute to the fabled religious procession in 1797 that ended a British siege.
Treat yourself to a piragua. Carts selling these tropical-flavored snow cones are parked on every corner in Old San Juan, and there's no better (or more delicious) way to beat the heat.
Spend an afternoon wandering the cool galleries of an art museum. Works by some of the island's greatest talents are featured at the Art Museum of Puerto Rico (Museo de Arte de Puerto Rico) , Puerto Rico Museum of Contemporary Art (Museo de Arte Contemporáneo de Puerto Rico) and Museo de San Juan .
Shop for island rum, designer labels, carnival masks and hand-carved santos on Cristo and Fortaleza streets, the prime retail districts in Old San Juan.
Take a sightseeing trip to the El Yunque National Forest . Rare orchids, ferns and palms flourish in this lush preserve in the Luquillo Mountains, one of the last habitats of the Puerto Rican Parrot.
Light a candle in the Catedral de San Juan Bautista and visit the marble tomb of Juan Ponce de León, the island's first governor.
Dine in a moonlit courtyard and listen to the two-note love song of the coqui frog, Puerto Rico's tiny national symbol.