Puerto Rico's capital makes a strong impression – even before you arrive on shore. Sailing into the harbor, keep an eye out for El Morro, a 16th-century citadel and UNESCO World Heritage Site, Castillo San Cristobal, a fearsome fortress built to scare away invaders, and La Fortaleza, the impressive official residence of the Governor of Puerto Rico. Once ashore, step back in time along cobbled streets and through squares flanked by pastel-colored Spanish colonial buildings. Or take your pick of beaches – will it be the golden-sanded Isla Verde, the snorkeler-approved El Escambrón, or the laid-back Ocean Park? Just don't leave San Juan without sampling a piña colada (or two) – the tropical cocktail was invented here in the 1950s.

Lose yourself in the beautiful chaos of Cartagena, where layers of cultural influence intersect to create a city rich in character. The walled Old Town – established in the 16th century and now a UNESCO World Heritage site – is best explored on foot. Stop by a street stall for fresh lulo juice before setting off to explore the labyrinthine streets, filled with shady plazas, ornate former mansions, and balconies overflowing with flowers. Just outside the historic walls, you'll find the colorful neighborhood of Getsemaní, where vivid murals adorn the facades of shops and galleries, and salsa music wafts from lively bars.