Originally founded as Santa Ana by the Spanish in the 1500s, Willemstad was renamed in the 17th century by Dutch traders, who found the natural harbor a perfect hideaway along the Spanish Main. Willemstad's historic pastel-colored, red-roofed town houses and natural harbor are on UNESCO's World Heritage List. Hemmed in by the sea, a tiny canal, and an inlet, its narrow streets are crosshatched by still narrower alleyways.