San Juan is the capital and most populous municipality in the Commonwealth of Puerto Rico, an unincorporated territory of the United States. San Juan was founded by Spanish colonists in 1521, who named it Ciudad de Puerto Rico (“Rich Port City”). Puerto Rico’s capital is the second oldest European-established capital city in the Americas, after Santo Domingo, in the Dominican Republic. Several historical buildings are located in San Juan; among the most notable are the city’s former defensive forts, Fort San Felipe del Morro and Fort San Cristobal, and La Fortaleza, the oldest executive mansion in continuous use in the Americas.