Old San Juan's 16th-century cobblestone streets, ornate Spanish town houses with wrought-iron balconies, ancient plazas, and eclectic museums together form a repository of the island's colorful history. Founded in 1521 by the Spanish explorer Juan Ponce de León, Old San Juan sits on an islet separated from the "new" parts of the city by a couple of miles and a few centuries. Today, however, it is culturally youthful and vibrant, reflecting the sensibilities of the stylish professionals, bohemian art crowd, and university students who people its streets. You'll find more streetfront cafés and innovative restaurants, more contemporary art galleries, and more musicians playing in plazas than anywhere else in San Juan.
Old San Juan slopes north, uphill, to Calle Norzagaray, which runs along the Atlantic shoreline and connects the twin fortifications of Castillo San Cristóbal and El Morro. On the north side of Calle Norzagaray you'll find a small neighborhood wedged between the city walls and the ocean—this is La Perla, a rough area you'd be wise to avoid. The west end of Old San Juan overlooks the bay, and it's here that the rugged, towering walls of the original city are most evident. On the south side, along Calle Gilberto Concepción de Gracia (also called Calle la Marina), you'll find cruise ships and commercial piers jutting into San Juan Harbor.