Blue cobbles and Spanish forts
Old San Juan, on an islet guarding the harbour, is one of the oldest cities under the US flag, with streets paved in blue-grey cobblestones and lined with brightly painted colonial houses. Two massive Spanish fortresses, Castillo San Felipe del Morro and Castillo San Cristóbal, form a National Historic Site. Beyond the old town, Condado and Isla Verde have hotels and beaches, and Santurce's La Placita market turns into a street party at night. Try mofongo, and salsa is everywhere. The piña colada is claimed as a San Juan invention.