Willemstad is the capital and largest city of Curaçao, an island in the southern Caribbean Sea that is a constituent country of the Kingdom …Willemstad is the capital and largest city of Curaçao, an island in the southern Caribbean Sea that is a constituent country of the Kingdom of the Netherlands. It was the capital of the Netherlands Antilles prior to that entity's dissolution in 2010. The historic centre of the city consists of four quarters: the Punda and Otrobanda, which are separated by the Sint Anna Bay, an inlet that leads into the large natural harbour called the Schottegat, as well as the Scharloo and Pietermaai Smal quarters, which are across from each other on the smaller Waaigat harbour. Willemstad is home to the Curaçao synagogue, the oldest surviving synagogue in the Americas. The city centre, with its unique architecture and harbour entry, has been designated a UNESCO World Heritage Site.